eduagarcia/scielo_abstracts · Datasets at Hugging Face

scl/1516-1439/S1516-14392023000100241.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100241

10.1590/1980-5373-mr-2022-0216

ENGINEERING, CHEMICAL

Universidade Federal do Rio Grande do Sul

null

Laboratory Evaluation of Tundish Covering Powders and Rice Hull Ash on Cleanliness for a SAE 1055 Modified Steel

Ferreira, Felipe Buboltz

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The continuous casting tundish is the last metallurgical reactor where molten metal flows before solidifying in the continuous casting mold. A tundish covering powder can be used for improving steel cleanliness; in this case it is named ‘active tundish slag’. The objective of this work is to evaluate, in laboratory, the effect of three kinds of tundish covering powders on cleanliness for a SAE 1055 modified steel - a Ca-aluminate, a Ca-Mg-aluminate, and an Al-silicate powder, analysing their interaction with rice hull ash. The forementioned materials were molten on liquid steel, representing different kinds of tundish covering powders which are used in the steel industry: a Ca-Mg-aluminate, an Al-silicate, and a Ca-aluminate. Experiments were performed with and without a top layer of rice hull ash, simulating industrial conditions. Distribution, density, and mean diameter of inclusions were measured through automated inclusion analyses. Through computational thermodynamics it was possible to evaluate deviation from saturation (considering Al2O3 and MgO from refractory) and slag viscosity. It can be stated that the Ca-aluminate tundish covering powder gives better results regarding cleanliness for the SAE 1055 modified steel under laboratory conditions.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100241&lng=en&tlng=en

17

scielo_articles/scl/1516-1439/S1516-14392023000100241.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Ferreira, Felipe Buboltz", "Klug, Jeferson Leandro", "Pereira, Julio Anibal Morales", "Bielefeldt, Wagner Viana", "Vilela, Antônio Cezar Faria" ]

null

[ "tundish covering materials", "tundish slag", "non-metallic inclusions", "automated inclusion analysis", "computational thermodynamics" ]

null

[ "Universidade Federal do Rio Grande do Sul", "Universidade Federal do Ceará" ]

scl/1516-1439/S1516-14392023000100250.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100250

10.1590/1980-5373-mr-2022-0475

ENGINEERING, CHEMICAL

Universidade Federal de São Carlos

null

Prediction of Elastic Parameters of Particle Reinforced Composites Using Finite Element Simulations

Schiavon, Fernando Luis

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The macroscopic properties of composite materials depend on the microscopic properties of the constituents and the geometric arrangement of their phases. Therefore, it is essential to predict heterogeneous materials’ mechanical properties by simulating microstructural finite element models. The present article aims to analyze particle reinforced composites composed of spherical alumina inclusions surrounded by a glass matrix using a tridimensional representative volume element. Herein, microstructures are artificially created considering a regular or random arrangement of the inclusions. Two materials systems previously studied in the literature were analyzed. The discretization of the models was performed to have periodic mesh, thus enabling the use of periodic boundary conditions. A finite element model is created using Abaqus software. Numerical results show that the macroscopic properties can be estimated with high accuracy for the temperature where linear matrix behavior stands. The predictions were compared to experimental data from the literature. The models with a regular arrangement of inclusions show a difference inferior to 10%, while random arrangements show a difference inferior to 3.9%. The developed numerical algorithms can be modified to include new features, such as other dispersed phase arrangements or nonlinear material behavior.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100250&lng=en&tlng=en

29

scielo_articles/scl/1516-1439/S1516-14392023000100250.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Schiavon, Fernando Luis", "Zanardi, Heloisa", "Zago, Igor Paganotto", "Angélico, Ricardo Afonso" ]

null

[ "Thermo-elastic properties", "representative volume element", "finite element analysis", "composites" ]

null

[ "Universidade Federal de São Carlos", "Instituto Federal de São Paulo", "Universidade de São Paulo" ]

scl/1516-1439/S1516-14392023000100240.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100240

10.1590/1980-5373-mr-2022-0516

ENGINEERING, CHEMICAL

Beijing University of Technology

null

Prediction of Residual Deformation and Stress of Laser Powder Bed Fusion Manufactured Ti-6Al-4V Lattice Structures Based on Inherent Strain Method

Gan, Mingju

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The development of additive manufacturing (AM) technology provides higher feasibility for designing and manufacturing lattice structures. However, the manufacturing process usually generates residual deformation and stress, and even produces cracking, thus affecting the performance of the parts. This work establishes a simulation model of the Ti-6Al-4V lattice structures during laser powder bed fusion (LPBF) based on the inherent strain method. Effects of geometric lattice parameters (inclination angle, rod diameter, rod length) on the residual deformation and stress are analyzed. Based on the simulation results, measures for improving the quality of the lattice structures are proposed. The proposed model and simulation results can provide theoretical references for designing and manufacturing the lattice structures during practical engineering applications of LPBF.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100240&lng=en&tlng=en

40

scielo_articles/scl/1516-1439/S1516-14392023000100240.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Gan, Mingju", "Wu, Qi", "Long, Lianchun" ]

null

[ "LPBF", "Inherent strain method", "Lattice structures", "Residual deformation", "Ti-6Al-4V" ]

null

[ "Beijing University of Technology" ]

scl/1516-1439/S1516-14392023000100239.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100239

10.1590/1980-5373-mr-2022-0444

ENGINEERING, CHEMICAL

Jiangsu University of Science and Technology

null

Effect of Microalloying on Microstructure and Mechanical Properties of Laser Weld of PHS Steel

Xia, Chunzhi

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The laser welded joint of 2000MPa cold rolled annealed hot pressed steel (PHS) is easy to break during cold rolling. In this paper, the laser welding method is used to butt weld four kinds of PHS2000 with a thickness of 3.5mm. The four kinds of PHS2000 steel are added with elements of 0% Nb, 0.04% Nb, 0.06% Nb + Cr and 0.08% Nb + Cr. The microstructure of the four kinds of welded joints is compared and analyzed. The mechanical properties of the four kinds of joints are compared through hardness test and tensile test. The results show that after adding 0.04% Nb, residual austenite appears in the weld zone and fully quenched zone, the width of columnar crystal decreases, the average hardness of the weld zone decreases from 595HV to 408HV, and the tensile strength increases from 608MPa to more than 800MPa. For chromium containing steel, the increase of niobium content can reduce the size of columnar crystal in weld zone.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100239&lng=en&tlng=en

14

scielo_articles/scl/1516-1439/S1516-14392023000100239.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Xia, Chunzhi", "Liu, Yinggang", "Song, Xiaoguo", "Cong, Famin" ]

null

[ "Laser welding", "Microalloying", "Weld microstructure", "Mechanical property" ]

null

[ "Jiangsu University of Science and Technology", "Harbin Institute of Technology" ]

scl/1516-1439/S1516-14392023000100238.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100238

10.1590/1980-5373-mr-2022-0196

ENGINEERING, CHEMICAL

Vels Institute of Science

null

Wear Behavior of Brass Based Composite Reinforced with SiC and Produced by Stir Casting Process

Mohan, E.

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The current investigation presents the wear-worn surface analysis of a silicon carbide-reinforced brass-based composite synthesized by stir casting. Wear behavior of the brass composite pin was analyzed by disc tribometer. Wear characterization studies and confirmation of elemental composition are investigated through scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) respectively. The worn surface of the synthesized brass composite was analyzed using atomic force microscopy (AFM). The aim of the investigation is to examine the surface morphology of the worn specimen. Based on the input constraints, the wear rate ranges from 0.0135 to 0.0893 mm3/min. The applied load is the predominant factor in the wear rate (83.75%). Sliding velocity has a minor effect on wear rate (1.06%). The improved surface roughness of 15.27 nm was produced on the worn surface. The novelty of the research work is to study the various surface parameters of the worn surface, such as roughness average, root mean square roughness, maximum height of the roughness, skewness, and kurtosis. These parameters were analyzed at different wear-worn surfaces of the synthesized brass composite. The wear-worn surface was deeply investigated and incorporated with SEM and AFM analysis.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100238&lng=en&tlng=en

30

scielo_articles/scl/1516-1439/S1516-14392023000100238.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Mohan, E.", "Anbuchezhiyan, G.", "Pugazhenthi, R.", "Prakash, F. Peter" ]

null

[ "Brass composite", "Silicon carbide", "Wear characterization", "Wear worn surface", "Atomic force microscopy" ]

null

[ "Vels Institute of Science", "Shanmuganathan Engineering College", "Mount Zion College of Engineering and Technology", "Saveetha Institute of Medical and Technical Sciences" ]

scl/1516-1439/S1516-14392023000100236.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100236

10.1590/1980-5373-mr-2022-0371

ENGINEERING, CHEMICAL

Shandong Jianzhu University

null

First-Principles Comparative Study of CuFeSe2 and CuFeS2

Liu, Xiaofan

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract In this paper, on the basis of first-principles, the CASTEP module of Materials Studio is used to calculate the band structures and optical properties of CuFeSe2 and CuFeS2 under the PBE pseudopotential of the generalized gradient approximation (GGA). The calculated results show that both CuFeSe2 and CuFeS2 are direct bandgap semiconductors with forbidden band widths of 0.64 eV and 1.06 eV, respectively. In the visible light range, the highest absorption coefficient of CuFeSe2 is 1.082×105 cm-1, the average reflectivity is 0.52, the maximum conductivity is 7.23 fs-1, the electrostatic constant is 65.9; the maximum value the highest absorption coefficient of CuFeS2 is 0.872×105 cm-1, the average reflectivity is 0.44, the maximum conductivity is 4.44 fs-1, the static dielectric constant is 52.32. The calculation results in this paper show that compared with CuFeS2, CuFeSe2 has advantages in photoconductivity and carrier separation, but has disadvantages in band gap and reflectivity. It is recommended to combine the two materials to prepare tandem solar cells.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100236&lng=en&tlng=en

25

scielo_articles/scl/1516-1439/S1516-14392023000100236.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Liu, Xiaofan", "Du, Jie", "Hua, Long", "Liu, Kegao" ]

null

[ "First-principles calculation", "energy band", "optical property", "CuFeSe2", "CuFeS2" ]

null

[ "Shandong Jianzhu University" ]

scl/1516-1439/S1516-14392023000100235.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100235

10.1590/1980-5373-mr-2022-0358

ENGINEERING, CHEMICAL

Ajloun National University

null

Plasma Hydrogenation of High-Carbon Structural Steel Wires under Different Prestressing Levels

El-Amoush, Amjad Saleh

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract High-carbon structural steel wires were prestressed to various levels in a plasma hydrogenation environment and then pulled in a slow strain rate test (SSRT). The effect of plasma hydrogenation under different prestressing levels on the material's tensile response and hydrogen embrittlement was noted. It was found that the ultimate tensile strength (UTS), yield strength, and ductility of the steel wire samples are decreased by plasma hydrogenation and prestressing levels. The more drastic decrease in the UTS, yield strength, and ductility is found in the plasma hydrogenated prestressing steel to a higher prestressing level. Moreover, the hydrogen embrittlement index of the steel wire samples is significantly increased by plasma hydrogenation and prestressing level. The highly plasma hydrogenated prestressing steel wire samples exhibit complete brittle fracture. A mixed mode of fracture, i.e., ductile and brittle, was observed at the surface of the plasma hydrogenated prestressing steel wire samples at lower levels. The hydrogen embrittlement areas at the fracture surfaces of steel wire samples are observed to increase with plasma hydrogenation and prestressing levels. More severe hydrogen cracking and blistering resulted in the fracture surfaces of plasma-hydrogenated prestressing steel wire samples with higher levels.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100235&lng=en&tlng=en

52

scielo_articles/scl/1516-1439/S1516-14392023000100235.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "El-Amoush, Amjad Saleh", "Al-Duheisat, Salman A." ]

null

[ "Plasma hydrogenation", "hydrogen embrittlement", "high-carbon steel wire", "prestressing" ]

null

[ "Ajloun National University", "Al-Balqa Applied University" ]

scl/1516-1439/S1516-14392023000100249.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100249

10.1590/1980-5373-mr-2022-0205

ENGINEERING, CHEMICAL

Universidade do Extremo Sul Catarinense

null

Green Ironmaking Industry: Production of Iron Pellets Using Lime Sludge

Rosso Neto, Lucio

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The use of alternative raw materials is essential for establishing a circular economy in the mineral and ironmaking sectors. Therefore, this study investigates the potential of lime sludge as fluxing material during pelletization and proposes an alternative route for the usage of waste. The pellets were manufactured with different binary basicity values (CaO/SiO2) (0.15-0.45) and bentonite (0.5-0.7 wt%) and fixed carbon (0.5-1.1 wt%) contents. The results demonstrated that lime sludge has significant potential for application in pelletization. Pellet quality was evaluated using drop number, mechanical strength, tumble index, porosity, and kinetic analyses. Pellets with the optimal composition using lime sludge withstood 3.6 drops/pellet, a tumble test of 1.57 wt.%, and a mechanical strength test of 214.83 kgf/pellet and exhibited a porosity of 31.28%. Lime sludge did not influence the reducibility of the iron-ore pellets. In the temperature range of 800-900 °C, the reaction was controlled by diffusion, with Ea between 179.89 and 233.10 kJ/mol.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100249&lng=en&tlng=en

37

scielo_articles/scl/1516-1439/S1516-14392023000100249.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Rosso Neto, Lucio", "Borgert, Carlos Henrique", "Oliveira, José Roberto de", "Grillo, Felipe Fardin", "Manfredi, Gabriel Valério Pereira", "Coleti, Jorge Luis", "Espinosa, Denise Crocce Romano", "Tenório, Jorge Alberto Soares", "Gesuino, David Batista", "Frizon, Tiago Elias Allievi", "Junca, Eduardo" ]

null

[ "Circular economy", "Solid waste", "Lime sludge", "Ironmaking" ]

null

[ "Universidade do Extremo Sul Catarinense", "Instituto Federal de Educação Ciência e Tecnologia do Espírito Santo", "Universidade Federal de Santa Catarina", "Universidade de São Paulo, Escola Politécnica" ]

scl/1516-1439/S1516-14392023000100251.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100251

10.1590/1980-5373-mr-2022-0357

ENGINEERING, CHEMICAL

Universidade Federal do ABC

null

Effect of Anodization on the Stress Corrosion Cracking Behavior of The AZ61 Magnesium Alloy in 0.1 M NaCl Solution

Okamoto, Fábio

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

In the present work, the AZ61 alloy, one of the most important commercial structural magnesium alloys, was anodized in three different alkaline electrolytes consisting of 3 M KOH + 0.15 M Na2SiO3 + 0.1 M Na2B4O7.10H2O, 3 M KOH + 0.5 M Na3PO4 and 3 M KOH + 0.50 M Na2SiO3. The treatment was conducted at two different current densities, 20 and 30 mA.cm-2 for 10 minutes. The anodized layers were characterized by scanning electron microscopy, X-ray diffractometry and X-ray photoelectron spectroscopy. The corrosion resistance was assessed by potentiodynamic polarization tests. The SCC behavior was studied using slow strain rate tests in 0.1 M NaCl solution at room temperature. Conventional tensile tests were also conducted in air. The susceptibility to SCC was dependent on the morphology of the anodized film. The composition of the electrolyte and the current density of the anodization treatment affected the SCC susceptibility of the AZ61 alloy. The best corrosion resistance and the lowest susceptibility to SCC were obtained for samples anodized in the borate-containing electrolyte at 30 mA.cm-2. The smooth and compact surface morphology of the anodized film obtained in this condition was the main reason for the improved SCC behavior of the AZ61 alloy.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100251&lng=en&tlng=en

57

scielo_articles/scl/1516-1439/S1516-14392023000100251.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Okamoto, Fábio", "Oliveira, Mara Cristina Lopes de", "Silva, Adenilson Almeida", "Droppa Jr, Roosevelt", "Antunes, Renato Altobelli" ]

null

[ "stress corrosion cracking", "AZ61", "magnesium alloy", "anodization" ]

null

[ "Universidade Federal do ABC", "Instituto de Pesquisas Energéticas e Nucleares" ]

scl/1516-1439/S1516-14392023000100233.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100233

10.1590/1980-5373-mr-2022-0273

ENGINEERING, CHEMICAL

Pontifícia Universidade Católica do Rio de Janeiro

null

Experimental Study of VHCF Fractographic Features of Conventionally and Additively Manufactured Steels

Andrade, M. F.

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Materials produced by additive manufacturing (AM) have been extremely related to literature. However, there is still unconsolidated knowledge about the fatigue life and respective mechanisms of initiation of cracks predominant in the VHCF regime for these materials. What has been observed in materials produced by conventional routes is that fatigue cracks tend to nucleate from intrinsic defects of the material located internally or in subsurface regions. The change in the evolution process of fatigue cracks leads to the formation of a characteristic morphology on the fracture surface, known as “fish-eye”. Another widespread aspect observed on the fracture surfaces is the formation of a fine granular area (FGA) nearby the initiation sites. This work aims to investigate the mechanisms of crack nucleation in VHCF of two distinct materials: conventional steel, DIN 34CrNiMo6 and AISI 316L stainless steel produced by L-DED. The ultrasonic tests were carried out at a frequency of 20±0,5 kHz and R= -1. The S-N curves were obtained and fracture surfaces were analyzed, fish-eye and FGA formation was verified. FGA sizes were compared to values estimated by empirical equations. FGA and fish-eye sizes were related to stress amplitude and maximum stress intensity factor (SIF).

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100233&lng=en&tlng=en

28

scielo_articles/scl/1516-1439/S1516-14392023000100233.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Andrade, M. F.", "Teixeira, M. C.", "Pereira, M. V." ]

null

[ "Ultrasonic fatigue", "FGA size", "fish-eye", "additive manufacturing (AM)" ]

null

[ "Pontifícia Universidade Católica do Rio de Janeiro" ]

scl/1516-1439/S1516-14392023000100260.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100260

10.1590/1980-5373-mr-2022-0468

ENGINEERING, CHEMICAL

University of Fallujah

null

Density Functional Theory Study of Metal-Organic Frameworks for Enhancement of Photo-Anode Properties

Kafi, Dhaidan Khalaf

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The optoelectronic properties of dye zinc and titanium-based metal-organic framework (MOF) compounds with regard to their application as photo-anode material characterized in solar cells were investigated. Analyses of the optoelectronic properties were performed on the MOF single crystal unit cell with adsorbed dye to determine the electronic and optical properties of the relevant materials. The electronic and optical properties were predicted by density functional theory (DFT) calculations. The results show that the absorption of light occurs for the examined MoF compounds from the near UV to the (visible) blue spectral range, at optical band gap sizes from 2.8 eV up to 3.88 eV. Dye sensitization of MOF with eosin Y or crown ether gave additive UV-Vis spectra. An improvement in band gap or an improved electron injection could be archived as well. Moreover, the light absorption does not solely depend on the linkers used, but also from the metal atoms in the secondary building unit. The fluorescence of MOFs depends on the linker and especially on the linker coordination and their rotation relative to each other. The utilizations of MOFs and their derivatives as electrodes, photoactive materials, charge carriers and additives in different solar cells are highlighted.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100260&lng=en&tlng=en

44

scielo_articles/scl/1516-1439/S1516-14392023000100260.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Kafi, Dhaidan Khalaf", "Ayyash, Adil N.", "Jabur, Younus Khalaf" ]

null

[ "MOF", "ZnO/crown", "TiO2/eosin Y", "dye-sensitized", "solar cell" ]

null

[ "University of Fallujah", "University of Anbar", "University of Anbar" ]

scl/1516-1439/S1516-14392023000100266.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100266

10.1590/1980-5373-mr-2023-0106

ENGINEERING, CHEMICAL

Universidade do Extremo Sul Catarinense

null

Production and Weathering Exposure of Thermochromic Coatings Used as Sensors to Protect Electricity Distribution Systems

Brogni, Ênio

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Currently, the overheating detection of electric system components is performed using thermal imaging devices, which depend on on-site regulation parameters, require skilled operators and suitable weather conditions. The development and application of innovative technologies to monitor hotspots has highlighted the use of sensors based on thermosensitive materials. In this study, a temperature sensor with thermochromic coating was developed. Thermochromic sensors covered with a varnish layer and nano-titanium oxide, in addition to thermochromic paint, were produced. A 23 experimental design was established to assess the performance of thermochromic sensors under artificial weathering conditions. Color measurements of the coatings were performed using the CIELAB method. Fourier-transform infrared (FTIR), UV-Vis (Ultraviolet-Visible), (thermogravimetric TGA, and Differential Scanning Calorimetry (DSC) analyses were performed on the sensors exposed to photodegradation to detect changes in the thermochromic coatings. The sensors exposed to thermodegradation, and salt spray weathering showed ΔE (total color difference) values below 1.50 points in the presence of TiO2. In comparison, the sensors exposed to photodegradation showed ΔE values above 10 points, and UV-Vis analysis revealed changes in the chemical structure of the coatings. These results demonstrate that the varnish layer and TiO2 can help minimize the degradation effects of temperature, light, and salinity.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100266&lng=en&tlng=en

39

scielo_articles/scl/1516-1439/S1516-14392023000100266.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Brogni, Ênio", "Duarte, Rodrigo da Costa", "Cercená, Rodrigo", "Colonetti, Emerson", "Peterson, Michael", "Cargnin, Maykon", "Dal-Bó, Alexandre Gonçalves" ]

null

[ "Thermochromic sensor", "Pigment", "Thermochromic dye", "Weathering" ]

null

[ "Universidade do Extremo Sul Catarinense", "Universidade do Extremo Sul Catarinense" ]

scl/1516-1439/S1516-14392023000100265.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100265

10.1590/1980-5373-mr-2022-0499

ENGINEERING, CHEMICAL

Xiamen University Malaysia

null

The Effect of Al-Cu Co-Dopants on Morphology, Structure, and Optical Properties of ZnO Nanostructures

Sugihartono, I.

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

We have synthesized ZnO nanostructure by using two-step methods i.e ultrasonic nebulizer and chemical bath deposition (CBD) at 95oC for two hours. The morphology, structural, reflectance, and photoluminescence properties have been characterized by the scanning electron microscope (SEM), the X-ray diffraction (XRD) measurement, ultraviolet-visible (UV-Vis) spectrophotometer, and photoluminescence spectrometer, respectively. Structurally, all samples possess polycrystalline hexagonal wurtzite structure, and the addition of Al-Cu decreases the crystallinity of ZnO nanostructures. Meanwhile, morphologically, the role of Cu dopants in Al-Cu co-doped ZnO nanostructures suppressed the growth of nanostructures in the c-axis. Hence, it can be used to modify the morphology of ZnO nanorods to nanodisks/nanosheets. Optically, the Al-Cu co-dopants can be used to shift the optical band gap energy of ZnO nanostructures to a lower wavelength (blueshift). The photoluminescence (PL) properties confirmed that the Al-Cu co-dopants have two peaks at the photon energy of 3.78 eV and 3.90 eV.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100265&lng=en&tlng=en

25

scielo_articles/scl/1516-1439/S1516-14392023000100265.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Sugihartono, I.", "Tan, S.T.", "Arkundato, A.", "Fahdiran, R.", "Isnaeni, I.", "Handoko, E.", "Budi, S.", "Budi, A.S." ]

null

[ "Al-Cu co-doped ZnO nanostructures", "structure", "morphology", "optical band gap energy", "photoluminescence" ]

null

[ "Xiamen University Malaysia", "Universitas Negeri Jakarta", "Universitas Negeri Jakarta", "Universitas Jember", "Indonesian Institute of Sciences" ]

scl/1516-1439/S1516-14392023000100264.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100264

10.1590/1980-5373-mr-2023-0016

ENGINEERING, CHEMICAL

Instituto Federal do Maranhão

null

Fast and Green Hematite (α-Fe2O3) and Akaganeite (β-FeOOH) Synthesis Using a Microwave-Assisted Hydrothermal Process with Single Precursor and No Stabilizing Agent

Diniz, Paulo Afonso F.

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

In this work, iron chloride (FeCl3.6H2O), a single reagent, was used to create the phases of hematite (α-Fe2O3) and akaganeite (β-FeOOH) without the need of organic solvents using the microwave-assisted hydrothermal technique (HM). X-ray diffraction demonstrated the efficacy of the HM technique in the generation of crystalline phases of α-Fe2O3 at 180oC and β-FeOOH at 120oC. The development of pseudo-cunic and stick-like particles was a result of changes in experimental variables, which also had a substantial impact on the materials structural characteristics. The nitrogen (N2) adsorption/desorption isotherms of the samples containing akaganeite and hematite phase resembled those of mesoporous materials. Hematite has a surface area of 25.44 m2 g-1, while akaganeite has a surface area of 110.60 m2 g-1, according to the calculation. Thermodifferential and thermogravimetric techniques were used to assess thermal degradation. The use of microwave hydrothermal synthesis was promoted as being quick, easy, affordable, and safe for the environment.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100264&lng=en&tlng=en

51

scielo_articles/scl/1516-1439/S1516-14392023000100264.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Diniz, Paulo Afonso F.", "Cavalcante, Kiany Sirley B.", "Souza, Josiane Carneiro", "Marques, Gleison N.", "Santos, Fernanda Hellen de S.", "Cutrim, Fiama M.", "Henriques, Raelma B.", "Mendonça, Leonardo T. B.", "Nascimento, Ulisses M." ]

null

[ "Hematite", "Akaganeite", "fast synthesis", "green metfhod", "high surface área" ]

null

[ "Instituto Federal do Maranhão", "Instituto de pesquisa científica", "Universidade Federal do Maranhão", "Universidade Federal do Maranhão", "Universidade Federal do Maranhão", "Universidade Federal do Maranhão" ]

scl/1516-1439/S1516-14392023000100263.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100263

10.1590/1980-5373-mr-2022-0624

ENGINEERING, CHEMICAL

Universidade Federal de Ouro Preto

null

Austenitizing Temperature Effects on the Martensitic Transformation and its Influence on Simulated Welding Residual Stresses in a Microalloyed-Steel

Abreu, Salvatore Giuliano Peixoto Tropia de

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

This study focused on the effects of different peak (austenitizing) temperatures (Tp) over the martensite start temperature (Ms) and its influence on the final residual stresses after welding simulation. For this purpose, the expansion coefficients obtained through physical (dilatometric) simulations of a high-strength low-alloy steel were considered for three peak temperatures: 1300 °C, 1150 °C, and 920 °C and a cooling rate of 25 °C/s. Aiming at clarifying the physical phenomenon behind GTAW welding, one carried out nonlinear transient thermomechanical finite-element (FE) analyses to reconstitute the welding process and simulate the subsequent formation of residual stresses in the HAZ. Once the heat source simulation was calibrated, four material models were created, one for each Tp, and a fourth model considering a constant expansion coefficient, without considering the martensite transformation for comparison. A Three-bar model was evaluated to isolate the effects of Tp (Ms) in the residual stresses. A composite plate model was also considered, in which the sheet HAZ was subdivided according to the reached peak temperature, and the respective material models were applied. The results show the importance of martensite transformation on the welding-induced residual stress and a clear trend of decreasing tensions with lowering the Tp, especially over HAZ.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100263&lng=en&tlng=en

32

scielo_articles/scl/1516-1439/S1516-14392023000100263.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Abreu, Salvatore Giuliano Peixoto Tropia de", "Porcaro, Rodrigo Rangel", "Faria, Geraldo Lúcio de", "Godefroid, Leonardo Barbosa", "Pereira, Igor Cezar", "Souza, Samuel da Silva de" ]

null

[ "Austenitizing temperature", "Martensite start temperature", "Welding-induced residual stress", "Numerical simulation", "Dilatometry" ]

null

[ "Universidade Federal de Ouro Preto", "Universidade Federal de Ouro Preto", "Universidade de São Paulo" ]

scl/1516-1439/S1516-14392023000100262.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100262

10.1590/1980-5373-mr-2022-0446

ENGINEERING, CHEMICAL

Zhengzhou Way Do Electronics Co. Ltd.

null

Preparation and Tribological Properties of a Superhydrophobic TB6 Titanium Alloy

Guo, Jialiang

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Superhydrophobic surfaces of conventional Ti-6Al-4V (TC4) titanium alloys facilitate drag reduction and anti-wear. However, the economical fabrication of a wear-resistant superhydrophobic Ti-10V-2Fe-3Al (TB6) titanium alloy for application in modern aerospace equipment remains to be achieved. Here, an efficient wear-resistant superhydrophobic TB6 titanium alloy surface using commercially available materials and processing equipment was fabricated through nanosecond laser texturing and facile chemical modification. The wettability of textured surfaces, including line and grid patterns, ablated at different laser scanning intervals were investigated and analyzed in terms of surface morphology and chemical composition. Moreover, the mechanisms of coefficient of friction changes on different surfaces under dry and water sliding conditions were studied based on surface morphology and wettability. Under dry sliding and water lubrication conditions, the average coefficient of friction of the prepared superhydrophobic surface can be reduced by 29% and 74%, respectively, compared with that of the original hydrophilic surface.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100262&lng=en&tlng=en

34

scielo_articles/scl/1516-1439/S1516-14392023000100262.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Guo, Jialiang", "Wang, Fang", "Liou, Juin J.", "Liu, Yuhuai" ]

null

[ "Laser texturing", "TB6 titanium alloy", "surface morphology", "superhydrophobic", "tribological properties" ]

null

[ "Zhengzhou Way Do Electronics Co. Ltd.", "Zhengzhou University", "Zhengzhou University", "Zhengzhou University" ]

scl/1516-1439/S1516-14392023000100261.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100261

10.1590/1980-5373-mr-2022-0529

ENGINEERING, CHEMICAL

Universidade do Estado do Rio de Janeiro

null

Numerical Prediction for the Effects of Welding Interpass Temperature on the Thermal History and Microstructure of Duplex Stainless Steels

Xavier, Carlos Roberto

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Numerical simulation was used to predict the thermal behavior and the resulting microstructure at the heat-affected zone (HAZ) of a 170 mm diameter and 3.5 mm thickness super duplex stainless steel (SDSS) UNS S32750 tube. In order to evaluate the thermal response from the model, a usual welding situation involving interpass temperature (IT) and its influence on the HAZ microstructure was exploited. Thus, two superimposed autogenous welding passes were simulated, the first clockwise with the tube in the room temperature and the second, counterclockwise, with the tube at the temperature of 250oC. Even subjected to successive thermal cycles and high interpass temperature, the proportion and morphology of the phases at the HAZ and Fusion Zone (FZ) did not present significant differences when comparing the two welding passes. Meanwhile, nitrogen losses should be avoided during welding in order to obtain a balanced microstructure in DSS welds, contributing to guarantee satisfactory toughness in addition to resistance to pitting corrosion. The predictions from the simulation were validated by using experimental results obtained from the autogenous TIG (Tungsten Inert Gas) process.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100261&lng=en&tlng=en

25

scielo_articles/scl/1516-1439/S1516-14392023000100261.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Xavier, Carlos Roberto", "Delgado Junior, Horácio Guimarães", "Rebello, Matheus Gomes", "Lisbôa, Raí Ramos", "Silva, Ana Carolina Martins", "Castro, José Adilson de" ]

null

[ "Welding interpass temperature", "duplex stainless steel", "numerical simulation", "thermal history", "microstructure" ]

null

[ "Universidade do Estado do Rio de Janeiro", "Centro Universitário de Volta Redonda", "Universidade Federal Fluminense" ]

scl/1516-1439/S1516-14392023000100259.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100259

10.1590/1980-5373-mr-2022-0308

ENGINEERING, CHEMICAL

Universidade Federal de Pernambuco

null

Electrical and Optical Properties of Poly(vinyl chloride)/ZnS Nanocomposites Exposed to Gamma Radiation

Guimarães, Nara E.

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Poly(vinyl chloride) (PVC) is considered one of the most versatile polymers due to its interaction with different additives. On the other hand, binary sulfides have wide applications as zinc sulfide (ZnS), one of the first discovered semiconductors. This study aims to synthesize a nanocomposite material containing nano ZnS in the PVC matrix with a surfactant as a compatibilizer agent to evaluate its optical and electrical properties when exposed to gamma radiation. Our results showed that adding ZnS at 0.5 wt% concentration in the PVC matrix promoted the system from insulating to the semiconductor material. Therefore, gamma radiation has played an important role in nanocomposites' optical and electrical properties with changes in electrical and electrical conductivity, constant dielectric parts, refraction index, optical band gap, and Urbach energy. Thus, our study points to the development of nanocomposite material, semiconductors, and features useful for applications in flexible electronics or optical-electronic devices.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100259&lng=en&tlng=en

65

scielo_articles/scl/1516-1439/S1516-14392023000100259.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Guimarães, Nara E.", "Ximenes, Érika R. B.", "Silva, Lindomar Avelino da", "Santos, Renata Francisca da Silva", "Araújo, Elmo Silvano", "Aquino, Kátia Aparecida da Silva" ]

null

[ "Optical-electronic devices", "gamma radiation", "gap band" ]

null

[ "Universidade Federal de Pernambuco" ]

scl/1516-1439/S1516-14392023000100252.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100252

10.1590/1980-5373-mr-2022-0449

ENGINEERING, CHEMICAL

Universidade Federal do Pará

null

Determination of Tensile Properties of Polyester - Industrial Waste Red Mud Composites Using Digital Image Correlation (DIC)

Rodrigues, Marcelo

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The Digital Image Correlation (DIC) technique is an important method of evaluating material strain fields. Composite materials have inherently heterogeneous elastic properties, in the function of the different phases present in the composition, whereat the traditional techniques of deformation evaluation may not be sufficient to determine the mechanisms that eventually contribute to the failure of the material. The present work were evaluated, the tensile mechanical properties of polyester matrix composites loaded with an industrial residue of red mud, with a mass fraction of 20%. The properties were surveyed using the conventional technique of strain gauge and compared with the data obtained through DIC. The results showed that the DIC technique was accurate in monitoring the displacements and determining the average deformation of the tested specimens, in addition to providing ample deformation fields, for the evaluation of failure mechanisms throughout the sample request process.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100252&lng=en&tlng=en

25

scielo_articles/scl/1516-1439/S1516-14392023000100252.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Rodrigues, Marcelo", "Ribeiro, Maurício Maia", "Cardoso, Robson Luis Baleeiro", "Ferreira, Ana Gabriele da Paixão", "Cardoso, Silmara Mota", "Silva, Jaciléa Campos da", "Ramos, Roberto Paulo Barbosa", "Rodrigues, Jean da Silva" ]

null

[ "Red mud", "tensile properties", "DIC", "polyester composites" ]

null

[ "Universidade Federal do Pará", "Instituto Federal de Educação, Ciência e Tecnologia do Pará", "Instituto Federal de Educação, Ciência e Tecnologia do Pará" ]

scl/1516-1439/S1516-14392023000100258.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100258

10.1590/1980-5373-mr-2022-0291

ENGINEERING, CHEMICAL

Universidade Federal do Rio de Janeiro

null

Deposition of Ti-Based Thin Films on AISI 1020 Steel Substrates Using the Cathodic Cage Plasma Deposition Technique

Silva, Raul Felipe Barros da

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The automotive industry is one of the largest industrial segments in the world market. The exhaust system of motor vehicles is responsible for the emission and treatment of toxic gasses released by the engine. In this sense, the application of titanium on an AISI 1020 steel substrate was carried out by plasma deposition using a cathode cage. The aim of this research was to evaluate the application of this material in the exhaust system of motor vehicles. The samples were characterized by scanning electron microscopy (SEM), confocal microscopy (CM), microhardness tests and corrosion resistance tests. The samples exhibited a thin film with higher titanium content and hardness than the uncoated sample. The corrosion potential also increased and the current density was lower than the uncoated sample. The conclusion is that the deposition of thin titanium films on AISI 1020 steel with CCPD has the potential to produce thin films.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100258&lng=en&tlng=en

73

scielo_articles/scl/1516-1439/S1516-14392023000100258.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Silva, Raul Felipe Barros da", "Cardoso, Wandercleiton", "Gontijo, Leonardo Cabral", "Pimentel, Bruno Poubel", "Viana, Pedro Rupf Pereira", "Galdino, André Gustavo de Sousa" ]

null

[ "Cathodic cage", "Plasma deposition", "AISI 1020 steel", "thin films", "titanium" ]

null

[ "Universidade Federal do Rio de Janeiro", "Instituto Federal de Educação Ciência e Tecnologia do Espírito Santo", "Università degli Studi di Genova" ]

scl/1516-1439/S1516-14392023000100257.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100257

10.1590/1980-5373-mr-2022-0370

ENGINEERING, CHEMICAL

Shandong Jianzhu University

null

Microstructure and Mechanical Properties of Thick 08Cr9W3Co3VNbCuBN Heat-Resistant Steel welded Joint by TIP TIG Welding

Wang, Yongbin

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

In this paper, the multi-layer multi-pass welding process was used to weld 115mm 08Cr9W3Co3VNbCuBN (G115) steel pipe, the gas tungsten arc welding (GTAW) was used in root pass welding, subsequent welding by dynamic hot wire gas tungsten arc welding (TIP TIG) welding method, while the post-weld heat treatment (PWHT) of 770°C × 10h was carried out afterward. The microstructure and mechanical properties of different zones of the welded joint were analyzed by OM, SEM, XRD, microhardness and impact tests. The results showed that the ferrite and martensite were observed in the weld metal (WM), the fine-grained heat-affected zone (FGHAZ) and the coarse-grained heat-affected zone (CGHAZ) consisting of prior austenitic grain boundaries (PAGBs) and martensite, and more precipitates including coarse M23C6 carbides with fine MX-type carbonitrides were observed inside the grain boundaries and grains. The hardness distribution patterns along different locations (Cover, Fill, Root) on the welded joint cross-section were the same, from base metal (BM) to WM hardness gradually increased, and WM hardness was the highest. WM impact toughness was worse than HAZ, impact fracture mode was a mixed tough-brittle fracture but biased towards brittle fracture.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100257&lng=en&tlng=en

33

scielo_articles/scl/1516-1439/S1516-14392023000100257.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Wang, Yongbin", "Liu, Peng", "Fan, Hongju", "Guo, Xinfang", "Wan, Fuwei" ]

null

[ "G115 steel", "multi-layer multi-pass", "TIP TIG", "precipitates", "microstructure", "mechanical property" ]

null

[ "Shandong Jianzhu University", "Power China Nuclear Engineering Co., Ltd." ]

scl/1516-1439/S1516-14392023000100216.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100216

10.1590/1980-5373-mr-2022-0325

ENGINEERING, CHEMICAL

Anna University

null

Experimental Investigation on the Effect of Stacking Sequence on Damage Resistance and Post-indentation Performance of Glass/Epoxy Laminates Under Different Loading Planes Using Acoustic Emission Monitoring

Bharathi, A. Usha

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract This research work focuses on the experimental investigation of indentation damage resistance and post-indented performance of different stacking sequence of glass/epoxy laminates using mechanical and acoustic responses. The laminates with stacking sequence, namely [0]12, [0/90]6S, [+45/-45]6S and [0/+45/-45/90]3S were subjected to normal and inclined indentation with acoustic emission monitoring. Quasi-static indentation (QSI) test was conducted on the center of the laminates using a hemispherical steel indenter with 12.7 mm diameter. The residual strength of the laminates was computed by conducting flexural after indentation test. Mechanical responses such as peak force, residual dent, linear stiffness and absorbed energy were employed to assess induced damages. The results reveal that the quasi-isotropic (QIS) laminates having better indentation damage resistance under 0o and 10o loading planes, whereas the angle-ply (AP) laminates performed well at 20o. Moreover, the normalised cumulative counts, energy rate, peak frequency, AE hits and sentry function were used to evaluate the damage initiation and propagation. Further, AE results show that the shear induced damage has been reduced in AP as compared with QIS laminates under 20o indentation plane. Finally, this study concluded that the QIS and AP laminates exhibited better indentation resistance under 0o and 10o, and 20o loading planes respectively.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100216&lng=en&tlng=en

39

scielo_articles/scl/1516-1439/S1516-14392023000100216.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Bharathi, A. Usha", "Arumugam, V.", "Kumar, C. Suresh" ]

null

[ "Indentation damage", "Acoustic emission", "Peak frequency", "Sentry function", "Residual flexural strength" ]

null

[ "Anna University", "Jeppiaar Engineering College", "Bharath Institute of Higher Education and Research" ]

scl/1516-1439/S1516-14392023000100255.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100255

10.1590/1980-5373-mr-2022-0467

ENGINEERING, CHEMICAL

Mahath Amma Institute of Engineering and Technology

null

Investigations on Tribological Behaviour of ZK60A Mg alloy-TiN Composites Synthesized via Powder Metallurgy Technique

Saravanan, H.

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The development in current manufacturing technology entails better wear resistance materials. Inthis study, ZK60A Mg alloy matrix composites reinforced with x wt.% (x = 0, 4, 8 and 12 wt.%) of TiN powders are developed through powder metallurgy (PM) route. The tribological behaviour of the composites under dry sliding conditions was estimated using Pin-on-disc instrument. The influence of the control parameters such as wt.% of TiN, applied load , sliding velocity and sliding distance on the wear rate and co-efficient of friction were analysed using Taguchi coupled grey relational approach GRA and L16 orthogonal array is selected for performing design of experiments. The lowest WR of 0.01147 mm3/m and 0.2446 COF formed at 12 wt.% of ‘R’, 9.81 N of ‘P’, 5.24 m/s of ‘V’ and 1000 m of ‘D’. From Analysis of variance (ANOVA), the wt.% of TiN powder (P = 82.68%) was observed as a primary factor controlling the WR and COF of composites. Finally, confirmation trials were performed to validate the results. SEM examination ensures homogeneous disbursement of TiN powders in the matrix alloy. Addition of reinforcement results in increase in density and porosity. The higher hardness observed at 12wt.% TiN incorporated Mg alloy composite.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100255&lng=en&tlng=en

33

scielo_articles/scl/1516-1439/S1516-14392023000100255.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Saravanan, H.", "Ravichandran, M.", "Veeman, Dhinakaran", "Alagarsamy, S.V." ]

null

[ "ZK60A Mg alloy", "TiN", "PM technique", "Tribological behaviour", "GR approach" ]

null

[ "Mahath Amma Institute of Engineering and Technology", "K. Ramakrishnan College of Engineering", "Chennai Institute of Technology" ]

scl/1516-1439/S1516-14392023000100254.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100254

10.1590/1980-5373-mr-2022-0390

ENGINEERING, CHEMICAL

Universidade de Brasília

null

Processing Biodegradable Blends of Hemicellulose with Polyhydroxybutyrate and Poly (Lactic Acid)

Mendes, Ívia Maria Lourenço

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The bottleneck of hemicellulose as a bio-based material is its processability and property drawbacks (softening and hydrophilicity). Thus, mixing other biopolymers can be an alternative. This article proposes blending hemicellulose (10−50 wt%) with polyhydroxybutyrate (PHB) and poly (lactic acid) (PLA), using acetic acid and chloroform as casting solvents to improve its processability and thermal properties. The materials were thermally (TGA - thermogravimetric analysis), chemically (FTIR - Fourier transformer infrared) and morphologically (SEM - scanning electron microscopy) characterized. Finally, a multicriteria decision analysis (MCDA) evaluated the materials’ properties to identify the optimum combination (casting solvent, biopolymer and hemicelluloses proportion) for producing an optimal blend. The MCDA established that the blend of hemicellulose:PHB (10:90 wt/wt) produced with acetic acid was optimum considering melting temperature and the crystallinity criteria. Moreover, higher hemicellulose concentration in the blends decreased the MCDA success rate, indicating the worst properties. PLA blends showed a higher degradation temperature than PHB. The PHB blends produced with acetic acid demonstrated improved properties when compared to chloroform, revealing its potential as a solvent.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100254&lng=en&tlng=en

47

scielo_articles/scl/1516-1439/S1516-14392023000100254.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Mendes, Ívia Maria Lourenço", "Fialho, Michaella Socorro Bruce", "Leão, Rosineide Miranda", "Silveira, Edgar A.", "Luz, Sandra Maria da" ]

null

[ "Hemicellulose", "polyhydroxybutyrate", "poly (lactic acid)", "blends", "solvent casting", "thermal properties" ]

null

[ "Universidade de Brasília", "Universidade de Brasília", "Universidade Paulista" ]

scl/1516-1439/S1516-14392023000100234.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100234

10.1590/1980-5373-mr-2022-0437

ENGINEERING, CHEMICAL

Manipal Academy of Higher Education

null

Effect of Surface Modified Montmorillonite Nanoclay on Tensile and Flexural Properties of Pineapple Leaf Fiber Reinforced Epoxy Composite

Muralishwara, K.

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Due to their biodegradability, affordability, low density, and numerous other benefits, natural fiber polymer composites are preferable to conventional GFRP in maritime applications. However, when exposed to moisture, their mechanical qualities deteriorate. A significant agricultural waste called pineapple leaf fiber (PALF) can be employed as reinforcement in epoxy matrices. Improved interfacial bonding between phases improves interfacial bonding and hence enhance mechanical and water absorption properties. Only evaluation of mechanical properties is undertaken in this paper. Nanoclay in 1.5 and 3 wt% was incorporated in epoxy resin via magnetic stirring and ultrasonication. PALF fibers were subjected to NaOH treatment and was analyzed using SEM and FTIR techniques. Hand layup and compression moulding were used to fabricate composites using a nanoclay-epoxy resin combination and chemically treated PALF (20 & 30 wt%). The combination of 30 wt% PALF and 1.5 wt% nanoclay results in the maximum mechanical properties, namely tensile and flexural properties. The results of SEM investigation of fractured specimens show that interfacial bonding in epoxy composites containing PALF is poor while that in epoxy composites containing PALF and 1.5 wt% nanoclay is excellent. Due to nanoclay agglomerations, bonding is inadequate at 3 wt% nanoclay, which lowers the mechanical properties.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100234&lng=en&tlng=en

31

scielo_articles/scl/1516-1439/S1516-14392023000100234.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Muralishwara, K.", "Fernandes, Lester", "Kalkura, Rushal", "Bangera, Sachin" ]

null

[ "Pineapple Leaf Fiber (PALF)", "natural fiber", "nanoclay" ]

null

[ "Manipal Academy of Higher Education" ]

scl/1516-1439/S1516-14392023000100256.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392023000100256

10.1590/1980-5373-mr-2022-0469

ENGINEERING, CHEMICAL

Universidad de Guadalajara

null

Optoelectronic Properties of CuSbS2 and Cu12Sb4S13 Thin Films for Thermoelectric Applications

Trejo-Zamudio, D.

2,023

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

This work presents a two-step procedure to obtain thin films with a combination of CuSbS2 and Cu12Sb4S13 phases for study in thermoelectric applications. The procedure consisted of the physical evaporation of sulfides layers (Sb2S3 and CuS) on glass substrates and the subsequent annealing of the samples in a N2 atmosphere. The characterizations by Raman spectroscopy and XRD revealed that the samples presented a varied percentage of Cu12Sb4S13 and CuSbS2. The results indicated that the percentage of phases depended on the initial thickness of the sulfide layers and the annealing temperature. The lower initial ratio between sulfide thicknesses and annealing temperature above 300 °C favored the formation of Cu12Sb4S13. However, the thermoelectric properties were improved when the phases coexisted in the thin film compared to samples with high percentages of Cu12Sb4S13. In this way, a sample with a power factor of 2.30 μW /cm∙ K2 at 60 ºC was identified.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392023000100256&lng=en&tlng=en

38

scielo_articles/scl/1516-1439/S1516-14392023000100256.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Trejo-Zamudio, D.", "Morales-Luna, M.", "Aruna-Devi, R.", "Pérez-García, C.E.", "Sosa-Domínguez, A.", "Quiñones-Galván, J.G.", "Moure-Flores, F.J. de", "Santos-Cruz, J." ]

null

[ "CuSbS2 chalcostebite", "Cu12Sb4S13 tetrahedrite", "thin films", "thermoelectric" ]

null

[ "Universidad de Guadalajara", "Universidad Autónoma de Querétaro", "Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey" ]

scl/1516-1439/S1516-14392021000300208.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000300208

10.1590/1980-5373-mr-2020-0569

ENGINEERING, CHEMICAL

Universidade Federal do Paraná

null

Plasma-Assisted Silver Deposition on Titanium Surface: Biocompatibility and Bactericidal Effect

Camargo, Eliziane da Rocha

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Dental implants are especially susceptible to bacterial adhesion and so microbial contamination. Several techniques have been explored in order to obtain implant surfaces enriched with silver (Ag). The main challenge is to obtain a bactericidal effect keeping the surface biocompatible. In this regard plasma-assisted deposition is a very attractive technique due to its versatility and low environmental impact. Thus, the present work aimed at evaluating the chemical stability, antibacterial activity, and biocompatibility of a commercially pure titanium (cp-Ti) surface containing very low amounts of plasma-deposited Ag. Ag deposition obtained by 10 minutes sputtering was able to promote antibacterial action (around 30%) on a clearly cytocompatible Ti/Ag surface with no apparent impact on biocompatibility. Taken together these results indicate that the proposed deposition process has a great potential for dental implant application with the advantage of using very small amounts of silver to achieve efficacy.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000300208&lng=en&tlng=en

37

scielo_articles/scl/1516-1439/S1516-14392021000300208.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Camargo, Eliziane da Rocha", "Hamdar, Kayam Zardo", "Santos, Maria Luiza Ferreira dos", "Burgel, Guilherme", "Oliveira, Carolina Camargo de", "Kava, Vanessa", "Cardoso, Rodrigo Perito", "Marino, Cláudia Eliana Bruno" ]

null

[ "silver plasma deposition", "bactericidal effect", "biocompatibility" ]

null

[ "Universidade Federal do Paraná", "Universidade Federal do Paraná", "Universidade Federal do Paraná", "Universidade Federal de Santa Catarina" ]

scl/1516-1439/S1516-14392022000100387.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392022000100387

10.1590/1980-5373-mr-2022-0187

ENGINEERING, CHEMICAL

Universidade Federal Fluminense

null

Microstructural Patterns, Microsegregation, Porosity, and Mechanical Properties of Hypoeutectic Al-Fe Alloy, and its Dependency with Solidification Thermal Parameters

Dantas, Bruno Silva

2,022

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Al-Fe alloys are usually used as packaging and structural materials, but in the recent years, there have been considered for possible applications in aerospace field. The solidification sequence in pure aluminum containing 1 wt.% Fe is described in term of the formation of macrostructure, microstructure, microsegregation, porosity and mechanical properties. This material was studied in the upward unidirectional solidification system under transient heat flow conditions. Differences in microstructure, microsegregation, porosity and mechanical properties such as ultimate tensile strength, elongation and microhardness, due to the thermal parameter effects were observed and discussed. Experimental growth laws relating cellular spacing to the cooling rate and solidification speed have been determined, indicating that the increase in thermal parameter have induced a refinement effect on cell morphology. Microsegregation profiles of Fe solute were experimentally determined from the central region of the cell to the intercellular region under different solidification speeds. The Fe microsegregation determined from central region of the cell (FS = 0) to the intercellular region (FS = 1) show a growing profile, in any case considered. However, the profiles move upward with the increase in solidification speed, which indicates that Fe solubility in solid, increases with the increase in solidification speed. The effect of the solidification thermal parameters and cellular spacing on the porosity content were experimentally investigated. The value of porosity content increased along the casting. These results have pointed out that porosity content is affected by solidification parameters and cellular patterns. Further, measurable effects of the thermal parameters, cellular spacing and porosity content on the mechanical properties were experimentally determined. It stands out among experimental results the influence of porosity on the mechanical properties of as-cast material. In any case analyzed, mechanical properties increase with decreasing porosity content.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392022000100387&lng=en&tlng=en

25

scielo_articles/scl/1516-1439/S1516-14392022000100387.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Dantas, Bruno Silva", "Garção, Wysllan Jefferson Lima", "Peixoto, Franciele de Matos", "Guimarães, Nilmara Almeida", "Tomaszewski, Ingrid Meirelles Salvino", "Ferreira, Alexandre Furtado" ]

null

[ "Aluminum alloys", "solidification", "alloying elements", "cell microstructure and mechanical properties" ]

null

[ "Universidade Federal Fluminense", "Instituto Federal do Rio de Janeiro", "Faculdade de Tecnologia de Cruzeiro" ]

scl/1516-1439/S1516-14392020000500201.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500201

10.1590/1980-5373-mr-2020-0269

ENGINEERING, CHEMICAL

Universidade Federal do Rio Grande do Sul

null

Response of a DIN 18MnCrSiMo6-4 Continuous Cooling Bainitic Steel to Different Plasma Nitriding Gas Mixtures

Dalcin, Rafael Luciano

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Continuous cooling bainitic steels has been widely used in industrial processes owing to its excellent mechanical properties and toughness. Although the surface properties of them are acceptable for many purposes, for their use in mechanical components like gears, it is necessary to improve their surface properties. Plasma nitriding treatments was carried out of a DIN 18MnCrSiMo6-4 steel at 500 °C, with three different nitrogen gas composition: 76, 24 and 5 vol.% nitrogen in hydrogen, for 3, 6 and 9 hours. The surfaces were characterized concerning the microstructure, microhardness, fracture toughness, nitrogen concentration and carbon composition, phase composition and residual stress states. Based on the results presented, layer growth constants (k) for different nitrogen gas composition was determined. The carbon profiles of samples indicate that there was decarburization during the plasma nitriding. The nitrided samples with thicker compound layers presented a fracture behavior dominated by the formation of Palmqvist cracks. X-ray phase analysis indicated the formation of biphasic compound layer on the surface of all nitrided samples with 76 and 24 vol.% nitrogen, while the nitrided samples with 5 vol.% nitrogen indicated the formation of monophasic compound layer. The diffusion zone presented compressive residual stresses with highest values near the surface.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500201&lng=en&tlng=en

31

scielo_articles/scl/1516-1439/S1516-14392020000500201.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Dalcin, Rafael Luciano", "Oliveira, Leonardo Fonseca", "Diehl, Carla Adriana Theis Soares", "da Silva Rocha, Alexandre" ]

null

[ "DIN 18MnCrSiMo6-4 Steel", "Plasma Nitriding", "Layer Growth Constant", "Fracture Toughness", "Phase Composition and Residual Stress Analysis" ]

null

[ "Universidade Federal do Rio Grande do Sul" ]

scl/1516-1439/S1516-14392020000400227.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400227

10.1590/1980-5373-mr-2020-0074

ENGINEERING, CHEMICAL

Universidade Federal de Santa Catarina

null

Metallic Droplet, Weld Pool Temperatures Evaluation and Pulsed Wave Formulation in the Pulsed GMAW

Silva, Régis Henrique Gonçalves e

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

This study analyzed the average temperature value of the metallic droplets and weldpool of the Pulsed GMAW welding process using 309L-Si electrode as the addition metal. The study was based on the formulation and evaluation of pulsed waves, starting from the equation of energy constant (or detachment constant), and waveforms from two commercial welding sources, that were evaluated and reproduced. The technique of filming by high speed infrared radiation was used for evaluation. The results point to a higher droplet temperature for a lower intensity of pulse current, due to longer dwell time at this level, and also revealing that a longer time in the base phase may be responsible for a further heating of the fusion pool.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400227&lng=en&tlng=en

9

scielo_articles/scl/1516-1439/S1516-14392020000400227.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Silva, Régis Henrique Gonçalves e", "Nogueira, Rodrigo Rodrigues", "Silva, Fernando Lucas dos Santos e", "Santos, Arthur Gustavo Moreira", "Brito, Uallas Henrique de Oliveira de" ]

null

[ "Droplet", "temperature", "pulsed", "GMAW", "waveform" ]

null

[ "Universidade Federal de Santa Catarina", "Universidade Federal do Rio de Janeiro", "Universidade Federal de Uberlândia" ]

scl/1516-1439/S1516-14392020000400225.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400225

10.1590/1980-5373-mr-2020-0246

ENGINEERING, CHEMICAL

North-West University

null

Sodium Silicate Cold-Bonded Chromite Pellets for the Ferrochromium Industry – Identifying a Suitable Process

du Preez, S.P.

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Chromite fines (defined as particles smaller than 6 mm) account for a significant fraction of mined South African chromite ore. These fines are pelletized to allow safe furnace smelting conditions. However, pelletization is an energy- and cost-intensive process that requires significant capital investment and has high operational costs as continuous curing temperatures of 1300 – 1500 °C are required. In this study, various cold-bonded pelletization processes were investigated to identify a process to prepare cold-bonded chromite pellets. A feasible process was identified and developed to produce mechanically strong chromite pellets using 3wt% sodium silicate-3 wt% SiO2 as the binder and KOH as an alkaline activator. The binding mechanism is based on the combined effects of sodium silicate and geopolymerization. It was determined that pellets cured at 75 °C had compressive strengths of 2.41 – 3.12 kN. The mechanical strength of these cold-bonded pellets where similar to, or exceed that of pellets currently used in the FeCr industry.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400225&lng=en&tlng=en

69

scielo_articles/scl/1516-1439/S1516-14392020000400225.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "du Preez, S.P.", "Maree, Z.", "Beukes, J.P." ]

null

[ "Chromite", "Cold-bonded", "Compressive strength", "Ferrochrome/ferrochromium", "Energy dependence" ]

null

[ "North-West University" ]

scl/1516-1439/S1516-14392020000400218.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400218

10.1590/1980-5373-mr-2020-0262

ENGINEERING, CHEMICAL

Universidade Federal de Minas Gerais

null

Hardness, Microstructure and Strain Distributions in Commercial Purity Aluminum Processed by Multi Directional Forging (MDF)

Almeida, Natanael Geraldo Silva

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Severe plastic deformation (SPD) of metals leads to their strengthening and grain refinement, but to low uniform elongations. Low Strain Amplitude Multi Directional Forging (LSA-MDF) is an important method for increasing this low uniform elongation. The application of workpieces of SPD-processed materials requires that their distributions of mechanical properties, microstructures and deformation be as homogeneous as possible. Analyses of these distributions after LSA-MDF have not been found in the literature, and are presented in the current investigation utilizing microhardness measurements, optical and electronic microscopy and finite element simulations. LSA-MDF causes higher strains, mcrohardeness and structural distortions in the central regions of the specimens than at their edges and corners. In addition, LSA-MDF utilizing confined compressions seems to be the preferred processing route, due to its ease and to the more homogeneous microhardness, microstructure and strain distributions in relation to other experimental procedures.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400218&lng=en&tlng=en

54

scielo_articles/scl/1516-1439/S1516-14392020000400218.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Almeida, Natanael Geraldo Silva", "Stemler, Pedro Malaquias Araújo", "Faria, Cleber Granato de", "Pereira, Pedro Henrique Rodrigues", "Aguilar, Maria Teresa Paulino", "Cetlin, Paulo Roberto" ]

null

[ "Aluminum", "Severe Plastic Deformation", "Multi Directional Forging", "Microstructures", "Distribution of strain and microhardness" ]

null

[ "Universidade Federal de Minas Gerais", "Centro Universitário Newton Paiva", "Universidade Federal de Minas Gerais", "Universidade Federal de Minas Gerais", "Universidade Federal de Minas Gerais" ]

scl/1516-1439/S1516-14392020000400224.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400224

10.1590/1980-5373-mr-2020-0100

ENGINEERING, CHEMICAL

Prince of Songkla University

null

Possible Use of Sepiolite as Alternative Filler for Natural Rubber

Masa, Abdulhakim

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The use of mineral fillers in rubber industry has been increasingly focused. Sepiolite is considered as one of the mineral fillers that exploits unique characteristics. This is due to its unique needle-like fibrous and a tunnel-like micro-pore channel structures. Therefore, adding this filler in natural rubber (NR) matrix would bring tremendous advantage. The study was carried out in the form of curing characteristics, tensile properties and morphology together with the dynamic properties. Filling sepiolite to NR has brought to a noticeable enhancement of curing characteristics, tensile properties and morphology. This is contributed to the distinctive structure of sepiolite itself, it provides a better dispersion to the NR. Surface roughness of the composites is visibly found which is responsible for the mechanical properties. Further verification was also monitored through the dynamic properties of the composites. The obtained profiles are in good agreement to the tensile properties and morphological characteristics observed.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400224&lng=en&tlng=en

32

scielo_articles/scl/1516-1439/S1516-14392020000400224.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Masa, Abdulhakim", "Krem-ae, Awatif", "Ismail, Hanafi", "Hayeemasae, Nabil" ]

null

[ "Natural Rubber", "Sepiolite", "Mineral Filler", "Tensile Properties", "Dynamic Property" ]

null

[ "Prince of Songkla University", "Prince of Songkla University", "Universiti Sains Malaysia" ]

scl/1516-1439/S1516-14392020000400223.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400223

10.1590/1980-5373-mr-2020-0133

ENGINEERING, CHEMICAL

Universidade Estadual de Campinas

null

The use of ECAP in the Microstructural Conditioning of the 355 Aluminum Alloy for Thixoforming*

Gregolin, A.

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The purpose of this study is to analyze the use plastic deformation (ECAP - Equal Channel Angular Pressing) in the preparation of the 355 aluminum for posterior use in Thixoforming. For this purpose, the 355 alloy, in the as cast state and after a pass of ECAP was heated to temperatures of 575 and 595 °C, enough to produce 45 and 55% of liquid fraction, for times of 0, 30, 60 e 90s. In these conditions, it is possible to obtain a refined globular structure with the size of a grain, close to 75 µm, globule size of 55 µm and high sphericity (around 0.66), parameters which are excellent for this kind of processing. Hot compression tests at the same temperatures and holding times determine the rheological behavior. Maximum processing strain was obtained around 1 MPa for the sample in ECAped condition against 4 MPa of the as cast condition, which corresponds to maximum viscosity around 105 Pa.s, (molten glass, clay), inferior to the as cast condition (11.5 * 105 Pa.s). Therefore, the ECAPed 355 alloy is an easily conformable material very likely to be applied to semisolid processing.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400223&lng=en&tlng=en

19

scielo_articles/scl/1516-1439/S1516-14392020000400223.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Gregolin, A.", "Facchini, C. A.", "Zoqui, E. J." ]

null

[ "Thixoforming", "Semisolid material", "Rheology", "ECAP", "355 aluminum alloy" ]

null

[ "Universidade Estadual de Campinas", "Instituto Federal de Educação Ciência e Tecnologia de São Paulo" ]

scl/1516-1439/S1516-14392020000400222.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400222

10.1590/1980-5373-mr-2020-0161

ENGINEERING, CHEMICAL

Instituto de Pesquisas Energeticas e Nucleares

null

Microstructural, Electrochemical and Localized Corrosion Characterization of the AA2198-T851 Alloy

Araujo, João Victor de Sousa

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

In the present work, the microstructure, electrochemical behavior and localized corrosion of the AA2198-T851 Al-Cu-Li alloy were studied. The microstructure was correlated with corrosion results obtained by immersion, gel visualization and scanning electrochemical microscopy (SECM) tests. Immersion and gel visualization tests showed high kinetics of corrosion attack during the first hours of immersion. SECM analyzes by means of surface generation/tip collection (SG/TC) mode detected hydrogen evolution generated during spontaneous corrosion from severe localized corrosion (SLC) sites on the metal surface. SECM results revealed sites of intense hydrogen evolution after 2 h of immersion and increased amounts of corrosion products after 4 h of immersion. Hydrogen evolution sites detected by SECM were associated with severe localized corrosion (SLC).

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400222&lng=en&tlng=en

74

scielo_articles/scl/1516-1439/S1516-14392020000400222.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Araujo, João Victor de Sousa", "Silva, Rejane Maria Pereira da", "Donatus, Uyime", "Machado, Caruline de Souza Carvalho", "Costa, Isolda" ]

null

[ "Aluminum alloy", "localized corrosion", "hydrogen evolution", "SLC", "SECM" ]

null

[ "Instituto de Pesquisas Energeticas e Nucleares" ]

scl/1516-1439/S1516-14392020000400221.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400221

10.1590/1980-5373-mr-2020-0164

ENGINEERING, CHEMICAL

Universidade Federal Fluminense

null

Analytical Modeling and Computer Simulation of the Transformation of Ellipsoids Nucleated on Random Parallel Planes

Sá, Gabriella Maria Silveira de

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

A considerable number of engineering materials is polycrystalline. Cahn proposed analytical expressions for transformations nucleated at the grain faces, triple junctions, and quadruple junctions. Those places are usually the places in which a new phase takes place. Cahn assumed that the new grain boundary nucleated phase grew as spheres. Nonetheless, the austenite grain boundary nucleated ferrite does not always grow as spheres. Bradley et al. demonstrated in a series of papers that a grain boundary nucleated ferrite allotriomorph is best described by an oblate ellipsoid. The reason for ellipsoidal growth is that the growth along the grain boundary plane is faster than the thickening into the austenite. Because of this, it is of interest to have analytical solutions and computer simulations of grain boundary nucleated transformations not only for spherical growth but also for ellipsoidal growth. In this work, we present a computer simulation of grain boundary nucleated transformations that grow as ellipsoids. The computer simulation results were compared with a new exact analytical expression obtained by Villa and Rios.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400221&lng=en&tlng=en

32

scielo_articles/scl/1516-1439/S1516-14392020000400221.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Sá, Gabriella Maria Silveira de", "Ventura, Harison da Silva", "Assis, Weslley Luiz da Silva", "Villa, Elena", "Rios, Paulo Rangel" ]

null

[ "microstructure", "grain boundaries", "analytical methods", "phase transformations", "ellipsoidal growth" ]

null

[ "Universidade Federal Fluminense", "University of Milan" ]

scl/1516-1439/S1516-14392020000400220.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400220

10.1590/1980-5373-mr-2019-0594

ENGINEERING, CHEMICAL

Universidade de São Paulo

null

Preparation of Laser-Modified Ti-15Mo Surfaces With Multiphase Calcium Phosphate Coatings

Santos, Marcio Luiz dos

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Multiphasic bioceramic scaffolds has been enhanced for dental and orthopedic applications. In this perspective, the laser surface texturing of metallic surfaces combined to bioactive calcium phosphate coatings have shown to be promising and economically feasible for biomaterial clinical applications. Ti-15Mo alloy samples were irradiated by pulsed Yb: YAG laser beam. The formation of HA and other calcium phosphates phases by biomimetic method should occur in the presence of Ca2+, PO43-, Mg2+, HCO3-, K+ and Na+. The modified surfaces were submitted to thermal treatment at 380 and 580°C. The results showed the processes of fusion and fast solidification from the laser beam irradiation, inducing the formation of stoichiometric α-Ti, TiO2 and non-stoichiometric titanium oxides, Ti3O and Ti6O with different oxide percentages depending on applied fluency (fluency of 0.023, 0.033, 0.040 and 0.048 J/mm2). The morphological and physicochemical properties have indicated the formation of a multiphase bioceramic coatings. It was observed the formation of amorphous calcium phosphate (ACP), octacalcium phosphate (OCP), and magnesium phosphate (Mg3(PO4)2) phases at 380°C, whereas β-TCP (tricalcium phosphate), OCP, and substituted β-TCP with Ca2,589Mg0,41(PO4)2 were obtained at 580°C. Therefore, the multiphasic bioceramic modified Ti-15Mo surface could enhance osteointegration for bone regeneration.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400220&lng=en&tlng=en

45

scielo_articles/scl/1516-1439/S1516-14392020000400220.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Santos, Marcio Luiz dos", "Almeida Filho, Edson de", "Silva, Vagner Pereira da", "Tranquilin, Ricardo L.", "Carnietto, Jéssica da Silva", "Guastaldi, Antônio C.", "Perreira, Regina Mara Silva", "Riccardi, Carla dos Santos" ]

null

[ "Ti-15Mo alloy", "biomimetic coatings", "calcium phosphates", "laser ablation" ]

null

[ "Universidade de São Paulo", "Universidade Estadual Paulista", "Universidade Federal do Rio Grande do Norte", "Universidade Estadual Paulista" ]

scl/1516-1439/S1516-14392020000400219.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400219

10.1590/1980-5373-mr-2020-0157

ENGINEERING, CHEMICAL

Universidade Federal do Rio Grande do Sul

null

Quantification of CTOD fracture toughness in welded joints to evaluate the efficacy of vibration stress relief compared to thermal stress relief

Moraes, Amauri Gomes de

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Resonant vibration residual stress relief (R-VSR) is an alternative method to post-weld heat treatments (PWHT) which is said to lead to less distortion and lower costs. The method of superposition of cyclic stresses and residual stresses, which can lead to localized yielding of the material, dislocation movement and subsequent stress relief. This article aims at investigating the efficiency of resonant vibration in the relief of residual stresses in welded joints of HSLA Domex700 steel sheets. Mechanical stress relief was compared to a common PWHT, and stress levels were then quantified through X-ray diffraction. Samples were also characterized by CTOD fracture toughness tests, fractographic analysis and tensile tests. Results indicate that the mechanical method was significantly less effective in relieving stresses in comparison with the PWHT, but led to apparent improvements in fracture toughness and in tensile tests. FWHM values indicated significant distortion for PWHT and less distortion for R-VSR.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400219&lng=en&tlng=en

41

scielo_articles/scl/1516-1439/S1516-14392020000400219.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Moraes, Amauri Gomes de", "Clarke, Thomas Gabriel Rosauro", "Diehl, Igor Luís" ]

null

[ "Resonant mechanical vibration", "residual stresses", "x-ray diffraction", "fracture toughness-ctod" ]

null

[ "Universidade Federal do Rio Grande do Sul" ]

scl/1516-1439/S1516-14392020000600220.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600220

10.1590/1980-5373-mr-2020-0214

ENGINEERING, CHEMICAL

Universidade Federal do Ceará

null

Building and Testing a Spin Coater for the Deposition of Thin Films on DSSCs

Teixeira, Edwalder Silva

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract A low cost spin coater was constructed in this work for the deposition of thin films of titanium dioxide (TiO2) on conductive substrate of FTO (fluoride doped tin oxide) with application on dye sensitized solar cells. The results showed a 95% precision between the speed values obtained by the software of C#sharp language and the spin values observed directly on the device. The TiO2 films deposited through the spin coater with different angular speeds were characterized by UV-Vis optical spectrum, scanning electron microscopy (SEM), atomic force microscopy (AFM) and electrical measurements on an active area of 0.25 cm2. The DSSCs assembled with the TiO2 films of double layer deposited by the spin coater had an efficiency value of 12.74%, while the cell with a single layer presented 4.05% efficiency. Therefore, it is concluded that the spin coater assembled in this study at low costs successfully can produce TiO2 electrodes for DSSCs.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600220&lng=en&tlng=en

52

scielo_articles/scl/1516-1439/S1516-14392020000600220.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Teixeira, Edwalder Silva", "Cavalcanti, Raphael Coelho", "Nunes, Vanja Fontenele", "Maia Júnior, Paulo Herbet França", "Lima, Francisco Marcone", "Pinho, Diego Caitano", "Souza Filho, Men de Sá Moreira de", "Almeida, Ana Fabíola Leite", "Freire, Francisco Nivaldo Aguiar" ]

null

[ "Spin coater", "spin coating", "DSSCs", "thin film", "TiO2" ]

null

[ "Universidade Federal do Ceará", "Universidade de Fortaleza", "Instituto Federal do Ceará", "Embrapa Agroindústria Tropical" ]

scl/1516-1439/S1516-14392020000600221.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600221

10.1590/1980-5373-mr-2020-0291

ENGINEERING, CHEMICAL

Shenyang Normal University

null

Study of Microstructure and Corrosion Behavior of Multilayered Ni Coatings by Ultrasound-assisted Electrodeposition

Li, Huawei

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Multilayered Ni coatings were successfully deposited on martensitic stainless-steel substrates by electrodeposition method with intermittent ultrasound. It is a novel kind of multilayered microstructure of stacked-up sandwiches, whose compositions of each monolayer are the same to those of its adjacent layers. The grains of ordinary Ni layers are columnar, vertically to the substrate surface, but the grains of ultrasonic Ni layers grow parallel along the substrate surface. By multilayered structure, the pinholes running through the coating were obviously inhibited, because the multilayered Ni coating can cover the whole surface of the substrate without the direct pinhole passages down to the substrate. Therefore, its corrosion mechanism is the uniform corrosion. For the ordinary Ni coating, the direct corrosion on the substrate can occur through the pinholes, which are the convenient passages for corrosive media to reach the substrate easily. This behavior can lead to the Fe/Ni galvanic corrosion, coating adhesion reduction, and quick formation of coating cracks in the ordinary Ni coating.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600221&lng=en&tlng=en

65

scielo_articles/scl/1516-1439/S1516-14392020000600221.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Li, Huawei", "Xing, Lingling", "Niu, Yunsong", "Zhu, Shenglong", "Wang, Fuhui" ]

null

[ "multilayered coatings", "ultrasound", "corrosion", "pinhole" ]

null

[ "Shenyang Normal University", "Institute of Metal Research", "Northeastern University" ]

scl/1516-1439/S1516-14392020000600222.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600222

10.1590/1980-5373-mr-2020-0344

ENGINEERING, CHEMICAL

Pontifícia Universidade Católica do Rio de Janeiro

null

Effect of an Alumina Supported Palladium Catalyst on the Magnesium Sulfate Decomposition Kinetics

Mello, Nathalli M.

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The sulfur related thermochemical water-splitting cycles are an important class of chemical processes considered for hydrogen production. Recently, the magnesium sulfate thermal decomposition has been reported as a potential unit operation in one of these cycles. Therefore, some interest has been observed in the use of catalysts to lower the activation energy of such reactions. In this context, the present manuscript reports the thermodynamics and kinetics modeling results associated with this reaction system in the presence of a Pd catalyst supported over γ-Al2O3. The presence of such species is responsible for shifting the decomposition temperature to lower values in at least 100 °C. It was observed that the magnesium content is still oriented towards MgO formation. The obtained results indicate that the Pd/Al2O3 catalyst could be a good alternative in reducing the thermal decomposition temperature as its presence was responsible for diminishing the process activation energy from 368.2 to 258.8 kJ.mol−1.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600222&lng=en&tlng=en

55

scielo_articles/scl/1516-1439/S1516-14392020000600222.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Mello, Nathalli M.", "Rego, Artur S. C.", "Brocchi, Eduardo A.", "Campos, José B. de", "Moura, Francisco J.", "Souza, Rodrigo F. M." ]

null

[ "Thermal decomposition", "kinetics", "MgO/MgSO4", "sulfur water-splitting cycles", "Pd catalyst" ]

null

[ "Pontifícia Universidade Católica do Rio de Janeiro", "Universidade do Estado do Rio de Janeiro" ]

scl/1516-1439/S1516-14392021000200217.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200217

10.1590/1980-5373-mr-2020-0401

ENGINEERING, CHEMICAL

AVIC Chengdu Aircraft Industrial

null

A Characterization of Hot Flow Behaviors of Invar36 Alloy by an Artificial Neural Network with Back-Propagation Algorithm

Zou, Zhen-yu

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

In order to investigate the hot deformation behaviors of Invar36 alloy, isothermal compressive tests were conducted on a Gleeble 1500 thermo-mechanical simulator at the temperatures of 873, 948, 1023, 1098 and 1173 K and the strain rates of 0.01, 0.1, 1 and 10 s−1. The effects of strain, temperature and strain rate on flow stress were analyzed, and a dynamic recrystallization type softening characteristic with unimodal flow behavior is determined. An artificial neural network based on back-propagation algorithm was proposed to handle the complex deformation behavior characteristics. The ANN model was evaluated in terms of correlation coefficient and average absolute relative error. A comparative study was performed on ANN model and constitutive equation by regression method for Invar36 alloy. Finally, the ANN model was applied to the finite element simulation, and an experimental study on trial hot forming of a V-shaped part was conducted to demonstrate the precision of the finite element simulation based on predicted flow stress data by ANN model. The results have sufficiently showed that the well-trained ANN model with BP algorithm is able to deal with the complex flow behaviors of Invar36 alloy and has great application potentiality in hot deformation.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200217&lng=en&tlng=en

24

scielo_articles/scl/1516-1439/S1516-14392021000200217.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Zou, Zhen-yu", "Li, Tao", "Zhang, Xiao-bo", "Zheng, Wei-tao", "Zhang, Yi", "Zhang, Yong-bing" ]

null

[ "Invar36 Alloy", "artificial neural network", "constitutive equation", "finite element simulation" ]

null

[ "AVIC Chengdu Aircraft Industrial" ]

scl/1516-1439/S1516-14392021000200223.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200223

10.1590/1980-5373-mr-2020-0488

ENGINEERING, CHEMICAL

Nanchang University

null

Analysis of Microstructure and Mechanical Properties of AZ31B Magnesium Alloy/AA6061 Aluminum Alloy Welded Joint by Ultrasonic Welding

Su, Zhanzhan

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

AZ31B magnesium alloy/AA6061 aluminium alloy welded structures have been widely used in the lightweight design of automobile bodies. To improve the joint strength, the ultrasonic spot welding (USW) solid state connection method is used in this paper. The results show that at a welding energy of 1540 J, there is evidence of melting in the weld joint. As the welding energy increases, the intermetallic compounds (IMCs) grow rapidly and form a reaction layer approximately 17 μm thick. The IMCs are mainly composed of the γ-Mg17Al12+β-Mg2Al3 phase, where the β-Mg2Al3 phase hardness is as high as 6.5 GPa and shows a typical pop-in phenomenon and the average hardness of the γ-Mg17Al12 cubic structure phase is 3.4 GPa. When the welding energy reaches 1540 J, the β phase rapidly grows, and the joint performance decreases rapidly. The fracture morphology indicates a cleavage fracture and is accompanied by a large number of secondary cracks.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200223&lng=en&tlng=en

31

scielo_articles/scl/1516-1439/S1516-14392021000200223.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Su, Zhanzhan", "Zhu, Zhengqiang", "Zhang, Yifu", "Zhang, Hua" ]

null

[ "AZ31B magnesium alloy/AA6061 aluminium alloy", "ultrasonic spot welding (USW)", "intermetallic compounds (IMCs)", "pop-in phenomenon", "joint performance" ]

null

[ "Nanchang University", "Jiujiang University" ]

scl/1516-1439/S1516-14392021000200222.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200222

10.1590/1980-5373-mr-2020-0334

ENGINEERING, CHEMICAL

Universidade Federal do Rio Grande do Sul

null

Two-Step Continuous Cooling Heat Treatment Applied in a Low Carbon Bainitic Steel

Castro, Pedro José de

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Thermo-mechanical treatments using continuous cooling after forging are an established method for producing bainitic steels, mainly because of the elimination of energy intensive additional heat treatment processes. The cooling is usually employed in an uncontrolled manner in the industrial sector, which can be detrimental to the resulting microstructural morphology and, consequently, to the final product properties. In this study, a new controlled two-step cooling route based on the principles of bainitic displacive growth was designed and applied in a 0.18C (wt-%) steel. Inverse finite element method was used on the cooling data to obtain the evolution of temperatures for the samples during cooling, allowing to assess point to point cooling rates. Investigations via X-ray diffraction, optical microscopy analysis and hardness testing revealed a variation of bainitic morphology, namely, the transition from granular bainite to lath-like bainite with relatively high hardness and constituents/phase boundaries than the pre-treated microstructure.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200222&lng=en&tlng=en

42

scielo_articles/scl/1516-1439/S1516-14392021000200222.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Castro, Pedro José de", "Silveira, Antonio Carlos de Figueiredo", "Ivaniski, Thiago Marques", "Turra, Cristiano José", "Epp, Jeremy", "Rocha, Alexandre da Silva" ]

null

[ "low carbon bainitic steel", "heat treatment", "granular bainite", "lath-like bainite" ]

null

[ "Universidade Federal do Rio Grande do Sul", "Leibniz-Institut für Werkstofforientierte Technologien", "University of Bremen" ]

scl/1516-1439/S1516-14392021000200221.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200221

10.1590/1980-5373-mr-2020-0398

ENGINEERING, CHEMICAL

Universidade Federal do Rio Grande do Sul

null

Analysis of Carbides in Multi-component Cast Iron Design Based on High Entropy Alloys Concepts

Pasini, W. M.

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Nowadays, the concept of high entropy alloys (HEAs) has expanded the limits of metallurgy and high-quality metallurgical HEAs ingots have already been successfully obtained on an industrial scale. High Chromium Cast Irons (HCCI) and Multi-Component Cast Irons (MCCI) are known to be a useful material for applications when abrasion resistance is required. Inspired by the concepts of high-entropy alloys, a base HCCI was modified, by adding other carbide-forming elements, at concentrations higher than what is currently used, in order to develop a new class of white cast iron, High Entropy White Cast Iron (HEWCI). The characterization of carbides precipitated during the HEWCI solidification was performed by scanning electron microscopy, energy dispersive spectroscopy, electron backscattered diffraction (SEM/EDS/EBSD) and X-ray diffraction (XRD). With the characterization techniques employed, the as-cast microstructure obtained of HEWCI is composed of approximately 50% of austenite matrix and 50% of different types of carbides, MC, M7C3 and M2C carbides.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200221&lng=en&tlng=en

34

scielo_articles/scl/1516-1439/S1516-14392021000200221.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Pasini, W. M.", "Bellé, M. R.", "Pereira, L.", "do Amaral, R.F.", "Barcellos, V. K. de" ]

null

[ "High entropy alloys", "High Chromium Cast Irons", "Multi-component Cast Irons", "Carbide-forming elements" ]

null

[ "Universidade Federal do Rio Grande do Sul" ]

scl/1516-1439/S1516-14392021000200220.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200220

10.1590/1980-5373-mr-2020-0529

ENGINEERING, CHEMICAL

Universidade Federal do Pará

null

On the Heat Capacity of Pure Elements and Phases

Ferreira, Ivaldo Leão

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Recently, a model was proposed to predict cv as a function of temperature from the absolute zero to the melting temperature applied. This solution was based on critical grain nucleation to determine the volume, which contains the total number of modes for a particular equilibrium and non-equilibrium state to calculate the density of state (DoS), which is strongly dependent on the nucleus radius for both pure element and compound. Electronic and rotational energies were regarded for both elements and compounds in this formulation. The anomalies associated with cv can be easily considered in terms of their entropies, independent of their nature, as a local change in the DoS. Comparisons of cv for elements and compounds are performed against Thermodynamics software simulations and experimental data.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200220&lng=en&tlng=en

44

scielo_articles/scl/1516-1439/S1516-14392021000200220.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Ferreira, Ivaldo Leão" ]

null

[ "Molar heat capacity", "Density of State", "Elements and compounds", "Computational Thermodynamics", "Anomalies of heat capacity" ]

null

[ "Universidade Federal do Pará" ]

scl/1516-1439/S1516-14392021000200219.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200219

10.1590/1980-5373-mr-2020-0402

ENGINEERING, CHEMICAL

Universidade de São Paulo

null

Effect of Fe2O3 Addition and Sintering Temperature on mechanical Properties and Translucence of Zirconia Dental Ceramics with Different Y2O3 Content

Alves, Manuel Fellipe R. P.

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The influence of Fe2O3 additions on the microstructure, mechanical properties and translucence of zirconia with 3 mol-% or 5 mol-% Y2O3 was evaluated. Samples were pressed with different thickness and sintered at 1475, 1500, 1550 and 1600°C for 2 h. Density, phases, microstructure, roughness, strength and translucency were analyzed. All samples showed densification greater than 99%. After sintering at 1600°C, the phase analysis revealed only tetragonal ZrO2 in samples with 3% Y2O3, while in samples with 5% Y2O3 the cubic ZrO2 phase was identified. Significant increase in the grain size was noted, when increasing the Y2O3 content from 3% to 5% from 0.8 µm to 2.3 µm for sintered samples at 1600°C. The strength was affected with Y2O3 content and no relevant influence of the Fe2O3 on density, microstructure or mechanical properties. Visible reflectance spectroscopy analyses, related to the CIELab scale, indicate variation in the contrast ratio as function of thickness of samples and coloring agent Fe2O3 content.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200219&lng=en&tlng=en

53

scielo_articles/scl/1516-1439/S1516-14392021000200219.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Alves, Manuel Fellipe R. P.", "Ribeiro, Sebastião", "Suzuki, Paulo A.", "Strecker, Kurt", "Santos, Claudinei dos" ]

null

[ "dental materials", "yttria-stabilized zirconia ceramics", "Fe2O3", "optical properties", "flexural strength" ]

null

[ "Universidade de São Paulo", "Universidade Federal de São João del-Rei", "Universidade do Estado do Rio de Janeiro" ]

scl/1516-1439/S1516-14392021000200218.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200218

10.1590/1980-5373-mr-2020-0469

ENGINEERING, CHEMICAL

Kunming University of Science and Technology,Kunming

null

Effect of MgO Content on Mechanical Properties of Directionally Solidified Pure Magnesium

Chen, Yuming

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The pure magnesium was fabricated by directional solidification, and the effect of the distribution characteristics of magnesium oxide (MgO) on the mechanical properties of pure magnesium was investigated. The statistical results showed that the area fraction, number and size of MgO were decreased gradually from the top region ingot to the bottom region ingot, and these reflected the advantages of directional solidification technology in the controllability of MgO distribution characteristics. The top parts of magnesium ingots have the highest tensile strength (44 MPa), which is mainly due to the presence of a large amount of the coarse MgO. Though the coarse MgO increases the strength obviously, it has harm for the ductility of magnesium. The top parts of magnesium ingots have higher ultimate tensile strength, but lower failure strain (13% and -21% respectively) than the ingot at the center. These results indicate that if the suitable size and amount of MgO existed in magnesium matrix, it could avoid the disadvantages of MgO and provide positive effect for both the strength and ductility of magnesium alloys.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200218&lng=en&tlng=en

40

scielo_articles/scl/1516-1439/S1516-14392021000200218.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Chen, Yuming", "Feng, Zhongxue", "Zhang, Wanneng" ]

null

[ "Magnesium oxide", "Directional solidification", "Tensile properties", "Diffusion mechanism" ]

null

[ "Kunming University of Science and Technology,Kunming" ]

scl/1516-1439/S1516-14392021000200216.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200216

10.1590/1980-5373-mr-2020-0332

ENGINEERING, CHEMICAL

Centro Paula Souza

null

Effect of Cold Rolling Path on the Deformation Textures Of C10300 Copper

Souza, Caio Rodrigues de

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Commercially free, C10300 Copper was submitted to cold rolling to 80% thickness reduction using three different rolling schedules. Rolling was conducted in 5, 8 and 11 rolling passes. Samples were then submitted to EBSD analysis at the surface and X-Ray Diffraction at the surface and mid-thickness to evaluate the deformation texture. EBSD analysis showed an increase in the intensity of the Copper component at the surface as the number of rolling passes decreased, and a very strong Goss component in all samples analyzed. X-ray diffraction analysis confirmed the strong copper component, but the Goss texture was much weaker when analyzed by X-ray diffraction, ultimately being nearly inexistent at mid thickness. The Brass component was very weak in EBSD analyses, but was found with higher intensity when texture was calculated using x-ray diffraction. The appearance of Goss component in surface grains can be explained by friction and shearing conditions in the roll-metal contact.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200216&lng=en&tlng=en

14

scielo_articles/scl/1516-1439/S1516-14392021000200216.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Souza, Caio Rodrigues de", "Monlevade, Eduardo Franco de" ]

null

[ "Deformation texture", "Cold rolling", "Copper" ]

null

[ "Centro Paula Souza", "Universidade de São Paulo" ]

scl/1516-1439/S1516-14392021000200225.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200225

10.1590/1980-5373-mr-2020-0377

ENGINEERING, CHEMICAL

Universidade Estadual Paulista

null

Synthesis of TiO2 Tubes Via Dissolution of TiOSO4 Rod Using H2O2

Montanhera, Maykon A.

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

We demonstrate here for the first time an original and facile approach to preparing titanium oxide (TiO2) tubes using hydrogen peroxide (H2O2) and titanyl (IV) oxysulfate (TiOSO4) as sacrificial templates. The method involves dissolving TiOSO4 powder in H2O2 solution and subsequently applying thermal treatment on the resulting amorphous precipitate. Prepared samples were characterized by X-ray diffraction, scanning electron microscopy (SEM) images, thermogravimetric (TG) analysis, and UV-vis analysis. Experimental results indicated that the samples exhibit tube-like structures with lengths of approximately 1.9 mm in diameter and 11.5 mm in length. Anatase and rutile phases were formed after annealing at different temperatures in air. The crystallite size estimated by Rietveld refinement showed an increase from 34.69 to 354.28 nm with an increase in the annealing temperature from 600 to 1000 °C. At the same time, the band gap values decreased from 3.14 to 2.97 eV. The electron density maps were calculated, and the electronic density was observed to increase from 497.56 e- Å-2 (600 °C) to 533.10e- Å-2 (740 °C) and decrease with the annealing temperature of samples. A possible mechanism for the formation of TiO2 tubes was proposed.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200225&lng=en&tlng=en

41

scielo_articles/scl/1516-1439/S1516-14392021000200225.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Montanhera, Maykon A.", "Venancio, Ricardo H. D.", "Pereira, Éder Alves", "Freitas, Renato G.", "Paula, Fernando R. de" ]

null

[ "TiO2 tubes", "titanyl sulfate", "template-free", "sacrificial template" ]

null

[ "Universidade Estadual Paulista", "Universidade Federal de Mato Grosso" ]

scl/1516-1439/S1516-14392021000200215.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200215

10.1590/1980-5373-mr-2020-0115

ENGINEERING, CHEMICAL

Universidade Estadual do Sudoeste da Bahia

null

Thermopolymerized Acrylic Resin Immersed or Incorporated with Silver Nanoparticle: Microbiological, Cytotoxic and Mechanical Effect

Pinheiro, Murilo Costa Rangel

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Associated with the use of removable prostheses, the development of candidiasis, called prosthetic stomatitis, is frequently observed. In view of the application of silver nanoparticles (AgNP) in dentistry that may offer antimicrobial effect, the aim of this study was to evaluate the effect of adding AgNP with different concentrations during thermopolymerization or immersion of acrylic in this substance in the properties antifungal, mechanical and cytotoxic. The groups were divided: addition of 1% silver nanoparticle solution (G1), addition of 2.5% silver nanoparticle solution (G2), addition of 5% silver nanoparticle solution (G3), immersed for 10 min in aqueous silver nanoparticle solution (G4), immersed for 24 hours in aqueous silver nanoparticle solution (G5). In the cytotoxicity assay, at all evaluation times, all groups showed cytotoxic effect (p <0.05) when compared to the control group (CG). For the microbiological assay, C. albicans reduction was observed only for G4 and G5 when compared to CG (p <0.05). The lowest resistance values were observed in the group with 5% silver nanoparticle (G3) incorporation (p <0.05). It was concluded that the thermopolymerized acrylic resin immersed in AgNP, G4 and G5 promoted microbiological reduction, cytotoxicity increase and flexural strength decrease at 5% concentration.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200215&lng=en&tlng=en

34

scielo_articles/scl/1516-1439/S1516-14392021000200215.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Pinheiro, Murilo Costa Rangel", "Carneiro, José Ailton Oliveira", "Pithon, Matheus Melo", "Martinez, Elizabeth Ferreira" ]

null

[ "stomatitis", "silver nanoparticle", "Polymethyl Methacrylate" ]

null

[ "Universidade Estadual do Sudoeste da Bahia", "Instituto e Centro de Pesquisas São Leopoldo Mandic" ]

scl/1516-1439/S1516-14392021000200214.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200214

10.1590/1980-5373-mr-2020-0381

ENGINEERING, CHEMICAL

Faculty of Mechanical Engineering

null

An Investigation on the Effect of Heat Treatment on the Compression Behavior of Aluminum Matrix Syntactic Foam Fabricated by Sandwich Infiltration Casting

Bolat, Çağın

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract In this research, syntactic foams including Al-7075 matrix and 2-4 mm low-cost pumice particles were manufactured via a novel casting method called as sandwich infiltration. According to physical evaluations, thanks to extremely porous structure of pumice, density values of the fabricated foams varied between 1.42 and 1.61 g/cm3. Porosity values were between 40.62% and 47.39%. Microstructural observations showed that there was a perfect infiltration between Al matrix and pumice particles because of correct process optimization (process pressure of 0.1 MPa, matrix melting temperature of 720°C and filler pre-temperature of 500°C). Furthermore, T6 treatment was applied to samples to comprehend effect of the aging on mechanical properties. The results indicated that there was an affirmative relation between the heat treatment and quasi-static compressive properties of the fabricated foams. The highest compressive strength, plateau stress and energy absorption values were measured as 64.4 MPa, 74.3 MPa and 34 MJ/m3 for heat treated samples. It was also observed that although the highest energy efficiency of 0.89 was calculated for heat treated sample, there was no relation between the heat treatment and efficiency. As for failure modes, as-cast samples exhibited ductile barreling characteristic whereas T6 treated foams indicated brittle v-shape fracture.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200214&lng=en&tlng=en

46

scielo_articles/scl/1516-1439/S1516-14392021000200214.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Bolat, Çağın", "Bilge, Gökhan", "Gökşenli, Ali" ]

null

[ "syntactic metal foam", "sandwich casting", "heat treatment", "compressive behavior", "deformation mechanism" ]

null

[ "Faculty of Mechanical Engineering", "Turkish Aerospace Industry" ]

scl/1516-1439/S1516-14392021000200213.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200213

10.1590/1980-5373-mr-2020-0503

ENGINEERING, CHEMICAL

Instituto Militar de Engenharia

null

Experimental and Analytical Investigation on the Effect of Heat Treatment Parameters on the Mechanical Properties of an API 5L X65 Steel

Moraes, Nicki Robbers Darciano Cajueiro de

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract High Strength Low Alloy steels (HSLA) for oil and gas pipelines should display high mechanical strength, toughness, ductility and weldability. In this work we studied the influence of quenching and tempering temperature on the yield strength, ultimate tensile strength, percent elongation and hardness of API 5L steel pipes in order to optimize heat treatments to be performed after hot induction bending of the material. The thermal cycles involved soaking temperatures of 880, 920 and 960 °C, cooling water at 15, 23 and 31 °C and tempering at 530, 600 and 670 °C. From this, experimental design techniques were used to reduce the number of experiments. The results from contour maps suggest that soaking temperatures of 910 and 950 °C and tempering between 540 and 610 °C were the most suitable for treatment, regarding mechanical strength. The variation of the water temperature was not significant for the assumed cooling conditions. The prediction regression models of the mechanical properties from the variables involved in the heat treatments showed a good fit between the experimental and predicted results, with correlation coefficient between 0.89 and 0.94.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200213&lng=en&tlng=en

19

scielo_articles/scl/1516-1439/S1516-14392021000200213.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Moraes, Nicki Robbers Darciano Cajueiro de", "Garcia, Julianna Magalhães", "Baêta Júnior, Eustáquio de Souza", "Cruz, Renato Batista da", "Brandao, Luiz Paulo" ]

null

[ "API 5L X65", "Heat treatment", "Hardness", "Tensile Test", "Statistical Analysis" ]

null

[ "Instituto Militar de Engenharia" ]

scl/1516-1439/S1516-14392021000200212.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200212

10.1590/1980-5373-mr-2020-0418

ENGINEERING, CHEMICAL

Fundação Centro Universitário Estadual da Zona Oeste

null

Sustainable Composites Based on Recycled High-density Polyethylene/mica

Almeida, Priscila de Oliveira

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Composites based on recycled high-density polyethylene (rHDPE) and muscovite mica, with different rHDE/mica ratios (100/0, 95/5, 90/10, 85/15 and 80/20, weight percentage) were prepared in an internal mixer with roller-type rotors at temperature of 170 ºC for 10 minutes. The materials obtained were characterized by tests of density, Shore hardness D and melt-flow index, along with infrared spectroscopy, thermogravimetry, differential scanning calorimetry and scanning electron microscopy. The hardness analysis confirmed the action of mica as a reinforcing load in the matrix, but this effect stabilized at around 15%. The TG analysis showed that the 85/15 composite presented slightly better performance than the 80/20, indicating that mica, up to 15%, caused disorganization of the polymer structure instead of reinforcing it. The DSC results revealed that the composites had slightly lower melting temperatures than the matrix. The FTIR spectrum indicated there was no chemical interaction between the rHDPE and mica.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200212&lng=en&tlng=en

19

scielo_articles/scl/1516-1439/S1516-14392021000200212.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Almeida, Priscila de Oliveira", "Gerardo, Camila Ferreira", "Leão, Ariadne Gonçalves de", "França, Silvia Cristina Alves", "Santos, Shirleny Fontes", "Bastos, Daniele Cruz" ]

null

[ "composites", "plastic lumber", "muscovite mica", "recycled high-density polyethylene" ]

null

[ "Fundação Centro Universitário Estadual da Zona Oeste", "Universidade Federal do Rio de Janeiro", "Centro de Tecnologia Mineral" ]

scl/1516-1439/S1516-14392021000200211.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200211

10.1590/1980-5373-mr-2020-0498

ENGINEERING, CHEMICAL

Universidade Federal de Ouro Preto

null

Proposition of an Empirical Functional Equation to Predict the Kinetics of Austenite to Ferrite Transformation in a Continuous Cooled IF-Ti-Stabilized Steel

Cezário, Ana Luiza Soares

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The kinetics of phase transformations in isothermal processes is well described by the classic JMAK model. However, it is known that most industrial facilities employ continuous cooling processes and, for this condition, the JMAK model is adapted but, sometimes, without success. Considering the importance to predict critical temperatures, the present work proposes an alternative empirical functional equation to describe the kinetics of steel phase transformation under continuous cooling, being useful when the JMAK use is not successful. In this study, the continuous cooling austenite to ferrite transformation was experimentally characterized by dilatometry for an IF-Ti-stabilized steel. The proposed equation was compared with the classic adapted JMAK model regarding to evaluate its efficacy to fit the dilatometric experimental data. Using the constants obtained by the both model fittings as input parameters, a computational simulation was performed to determine the CCT diagram of the IF-Ti steel. The proposed functional equation was efficient to predict the critical temperatures, the kinetics of austenite decomposition and the CCT diagram of the studied steel. The results predicted by the proposed model greatly met the experimental data measured by dilatometry.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200211&lng=en&tlng=en

44

scielo_articles/scl/1516-1439/S1516-14392021000200211.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Cezário, Ana Luiza Soares", "Faria, Geraldo Lúcio de" ]

null

[ "Empirical equation", "phase transformation", "continuous cooling", "IF-Ti-stabilized steel" ]

null

[ "Universidade Federal de Ouro Preto" ]

scl/1516-1439/S1516-14392021000200210.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200210

10.1590/1980-5373-mr-2020-0435

ENGINEERING, CHEMICAL

Centro Federal de Educação Tecnológica de Minas Gerais

null

Investigation of the effects of skewness Rsk and kurtosis Rku on tribological behavior in a pin-on-disc test of surfaces machined by conventional milling and turning processes

Ba, Elhadji Cheikh Talibouya

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Friction and wear are influenced by the surface conditions of the material, since there is deformation, segregation, generation of oxide films, among others. Roughness is an important characteristic in tribological studies, where the parameters of skewness and kurtosis have greater influence than the conventional parameters Ra and Rq. This study is aimed to investigate the influence of the parameters of skewness Rsk and Rku kurtosis on the surface of the USI AR 360 steel machining by the milling and turning processes in the pin-on-disc sliding wear test. Results showed that surfaces with the same Ra and Rq could be distinguished by the skewness parameter. Different behaviors were observed in the analysis of friction curves, where the skewness effect showed a tendency to reduce the friction coefficient. It was also observed that the feed marks orientation in relation to the sliding direction can influence the tribological behavior of the surfaces.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200210&lng=en&tlng=en

44

scielo_articles/scl/1516-1439/S1516-14392021000200210.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Ba, Elhadji Cheikh Talibouya", "Dumont, Marcello Rosa", "Martins, Paulo Sérgio", "Drumond, Ramon Martins", "Martins da Cruz, Matheus Philippe", "Vieira, Vitor Ferreira" ]

null

[ "Friction coefficient", "Wear coefficient", "Roughness", "Skewness", "Kurtosis", "Asperities", "Tribology" ]

null

[ "Centro Federal de Educação Tecnológica de Minas Gerais", "Pontifícia Universidade Católica de Minas Gerais", "Universidade Federal de Minas Gerais" ]

scl/1516-1439/S1516-14392021000200224.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200224

10.1590/1980-5373-mr-2020-0369

ENGINEERING, CHEMICAL

Universidade Federal do Rio de Janeiro

null

Influence of Cu Addition and Autoclave Sterilization on Corrosion Resistance and Biocompatibility of NiTi for orthodontics Applications

Barros, Camila Dias dos Reis

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Commercial archwires NiTiCu (Ormco) and NiTi (Morelli) and samples of the corresponding raw materials were tested to assess the influence of Cu addition and sterilization on the corrosion resistance and biocompatibility. Raw materials samples and commercial archwires exhibited similar corrosion resistance when compared. The addition of Cu decreased the corrosion resistance of NiTi alloy, whiling the sterilization process had no influence. The biocompatibility tests were carried out in different extracts of the alloys and no cytotoxicity effects were observed for the ionic concentrations used. SEM and Confocal laser analysis permitted to observe the localized corrosion morphology obtained after anodic polarization tests. Although Cu addition on NiTi can be introduced to better adjust the mechanical resistance, this third element induced detrimental effect on the corrosion resistance of raw materials and commercial archwires.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200224&lng=en&tlng=en

27

scielo_articles/scl/1516-1439/S1516-14392021000200224.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Barros, Camila Dias dos Reis", "Gomes, José Antônio da Cunha Ponciano" ]

null

[ "corrosion", "NiTi", "NiTiCu", "archwire", "NaCl", "autoclaving", "sterilization", "confocal microscopy" ]

null

[ "Universidade Federal do Rio de Janeiro" ]

scl/1516-1439/S1516-14392020000500202.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500202

10.1590/1980-5373-mr-2020-0211

ENGINEERING, CHEMICAL

Universidad Nacional Autónoma de México

null

Synthesis of PLA/SBA-15 Composite Scaffolds for Bone Tissue Engineering

Chanes-Cuevas, Osmar Alejandro

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Composite materials are used in bone tissue engineering because they mimic the structure of the extracellular matrix of bone. In this work, polylactic acid (PLA) fiber scaffolds prepared by air-jet spinning technique, were doped with different concentrations of SBA-15 ceramic (0.05, 0.1, and 0.15 wt%). The SBA-15 ceramic powder was made by the Sol-Gel process. Physicochemical characterization of PLA, SBA-15, and composite fiber scaffold was done by XRD, SEM, BET, FTIR, TGA, mechanical test, and biocompatibility assay, which were performed in a cell culture model with osteoblast cells. Our results showed a random nanofibers composite scaffold with an improvement in the physicochemical properties. The PLA fiber diameter increases as increases the content of SBA-15, and the mechanical properties were dose-dependent. SBA-15 shows the well-ordered mesoporous hexagonal structure with a pore size of 5.8 ± 0.2 nm and a specific surface area with a value of 1042 ± 89 m2/g. PLAfibers and composites have thermal stability up to 300°C, and thermal decomposition in the range 316-367°C. In vitro biocompatibility results showed that PLA/SBA-15 composite scaffold had no cytotoxicity effect in terms of cell adhesion and viability of osteoblast cells. Furthermore, the doped SBA-15 with 0.05% wt onto the polymer matrix could be useful in biomedical applications for bone tissue engineering.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500202&lng=en&tlng=en

71

scielo_articles/scl/1516-1439/S1516-14392020000500202.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Chanes-Cuevas, Osmar Alejandro", "Arellano-Sánchez, Ulises", "Álvarez-Gayosso, Carlos Andrés", "Suaste-Olmos, Fernando", "Villarreal-Ramírez, Eduardo", "Álvarez-Fregoso, Octavio", "García-Hipólito, Manuel", "González-Alva, Patricia", "Álvarez-Pérez, Marco A." ]

null

[ "Silica mesoporous material", "air-jet spinning", "fiber spun mats", "composites scaffold", "cell-material interaction", "bone tissue engineering" ]

null

[ "Universidad Nacional Autónoma de México", "Universidad Autónoma Metropolitana-Iztapalapa", "Universidad Nacional Autónoma de México", "Instituto de Fisiología Celular", "Instituto de Investigaciones en Materiales" ]

scl/1516-1439/S1516-14392021000200226.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200226

10.1590/1980-5373-mr-2020-0335

ENGINEERING, CHEMICAL

Public University of Navarre

null

Effect of Ti on Microstructure, Mechanical Properties and Corrosion Behavior of a Nickel-Aluminum Bronze Alloy

Rivero, Pedro J.

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Nickel-aluminum bronze (NAB) alloys are suitable, in cast condition, to be used in marine propellers due to its excellent behavior avoiding erosion and cavitation as well as corrosion. A complex microstructure, intrinsic to this copper base system, is the result of a well-controlled chemical composition. There are few works related to the effect of adding small quantities of specific chemical elements on NAB alloys properties. The aim of this paper is to study the effect of Ti on the microstructure, mechanical properties, and corrosion behavior of a particular NAB alloy, CuAl10Fe5Ni5 (C95500), and the comparison to the Ti-free NAB alloy. Although the as- cast microstructure is very similar for both materials, the addition of only 120 ppm Ti leads to a significant grain refinement that plays a key role on the mechanical properties. It has been observed an increase in both microhardness and nanohardness as well as in the resultant Young moduli values, meanwhile no significant impact on the corrosion susceptibility has been observed.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200226&lng=en&tlng=en

39

scielo_articles/scl/1516-1439/S1516-14392021000200226.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Rivero, Pedro J.", "Berlanga, C.", "Palacio, J. F.", "Biezma-Moraleda, M. V." ]

null

[ "Nickel–aluminum bronze (NAB)", "microstructure", "grain reinforcement", "nanohardness", "corrosion" ]

null

[ "Public University of Navarre", "Centre of Advanced Surface Engineering", "University of Cantabria" ]

scl/1516-1439/S1516-14392020000500203.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500203

10.1590/1980-5373-mr-2020-0285

ENGINEERING, CHEMICAL

Universidade Federal do Paraná

null

Comparison of the Silica Fume Content for High-Strength Concrete Production: Chemical Analysis of the Pozzolanic Reaction and Physical Behavior by Particle Packing

Campos, H.F.

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Silica fume (SF) is the most commonly mineral admixture used for the production of high-strength concrete (HSC) due to its chemical characteristics of pozzolanic reactivity and physical filling effect. The objective of the present work is to compare the SF content by the chemical analysis of the pozzolanic reaction and the physical behavior by particle packing techniques. The first step of the study was to analyze the SF content to consume the calcium hydroxide (CH) produced during the hydration of Portland cement (PC), based on stoichiometric calculations. Then, the SF content for maximum packing density was obtained using analytical particle packing models and experimental tests. The compressive strength of the pastes was also measured. The results showed that the theoretical SF content for consuming CH is 15.6%, replacing PC. According to the packing density analytical models, the ideal SF content is 15% of the total fine materials. However, the experimental results indicated the use of a smaller SF content (10%). This difference between theoretical and experimental results is probably due to the high specific surface of the SF, which results in important surface forces between the grains, particle agglomeration and difficulty in SF densification with water.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500203&lng=en&tlng=en

43

scielo_articles/scl/1516-1439/S1516-14392020000500203.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Campos, H.F.", "Klein, N.S.", "Marques Filho, J." ]

null

[ "Silica fume", "packing density", "pozzolanic reaction", "high-strength concrete" ]

null

[ "Universidade Federal do Paraná" ]

scl/1516-1439/S1516-14392020000500205.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500205

10.1590/1980-5373-mr-2019-0591

ENGINEERING, CHEMICAL

Universidade do Estado do Rio de Janeiro

null

Optimization of Espresso Spent Ground Coffee Waste Extract Preparation and the Influence of its Chemical Composition as an Eco-friendly Corrosion Inhibitor for Carbon Steel in Acid Medium

Costa, Marina A. J. L. da

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

This work proposes the reuse of spent ground coffee waste (SCG) extracts as eco-friendly corrosion inhibitors for carbon steel in acid medium, and the correlation between their anticorrosive efficiency and chemical composition. The extraction method was optimized using a central composite design, and the chemical composition of the extracts was accessed using UV-Vis spectrometry, HPLC, and ICP-OES. EIS and Potentiodynamic Polarization (PP) tests evaluated the anticorrosive properties of the extracts. Total phenol content ranged from 93 mg L-1 to 219 mg L-1 Gallic Acid Equivalent. The highest concentration of phenolic compounds was observed for syringic acid (78.67 mg L-1), while the lowest concentration was verified for (-)-epigallocatechin-3-O-gallate (0.01 mg L-1). The Pearson correlation coefficient showed no correlation between the Rct and the total phenol content, although, positive correlations with the Rct was observed for caffeic acid, (+)-catechin, ferulic acid, and protocatechuic acid. EIS analysis revealed that all of the extracts could act as corrosion inhibitors. The best performance was verified for C3 extract (IE % = 94.83%). PP tests showed that this extract acted as a mixed inhibitor, with a predominant cathodic effect. Therefore, the valorization of the extracts as corrosion inhibitors was successfully achieved.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500205&lng=en&tlng=en

48

scielo_articles/scl/1516-1439/S1516-14392020000500205.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Costa, Marina A. J. L. da", "Gois, Jefferson S. de", "Toaldo, Isabela M.", "Bauerfeldt, Ana Clara Favilla", "Batista, Diego B.", "Bordignon-Luiz, Marilde T.", "Lago, Dalva C. B. do", "Luna, Aderval S.", "Senna, Lilian F. de" ]

null

[ "Spent ground coffee", "Chemical Characterization of Food", "Waste Management", "Pearson correlation", "Green Chemistry", "Corrosion Inhibitor" ]

null

[ "Universidade do Estado do Rio de Janeiro", "Universidade Federal de Santa Catarina" ]

scl/1516-1439/S1516-14392020000600210.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600210

10.1590/1980-5373-mr-2020-0363

ENGINEERING, CHEMICAL

Centro Federal de Educação Tecnológica Celso Suckow da Fonseca

null

Investigation into the Impact Toughness of API 5L X80 Steel Weldments and its Relationship with Safe Welding Procedures

Carbos, Thiago Rodrigues

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

API 5L X80 steels are widely used in welded pipes in the petroleum industry. However, microstructural changes in the heat affected zone are a concern when welding such pipes due to the potential formation of regions with low toughness. Despite all the research concerning mechanical properties of welded joints, the acceptance criteria for the qualification of welding procedures are still limited. Welded joints do not always guarantee the safe operation of industrial equipment, because the current Standards adopted are not able to evaluate the properties at some critical regions of the welded joint. This work studied the characteristics of a girth welded joint and showed evidences of low toughness at 0.5 mm from the fusion line due to the micro-phases necklacing the prior austenite grain boundaries. As this feature is not considered by the current Standards for approval of welding procedures, this work proposes an alternative approach to improve the safety of welded structures.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600210&lng=en&tlng=en

77

scielo_articles/scl/1516-1439/S1516-14392020000600210.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Carbos, Thiago Rodrigues", "Jorge, Jorge Carlos Ferreira", "Souza, Luís Felipe Guimarães de", "Bott, Ivani de Souza", "Mendes, Matheus Campolina" ]

null

[ "API 5L X80", "welded joints", "MA constituent", "HAZ", "impact toughness", "microstructure" ]

null

[ "Centro Federal de Educação Tecnológica Celso Suckow da Fonseca", "Pontifícia Universidade Católica do Rio de Janeiro" ]

scl/1516-1439/S1516-14392020000600211.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600211

10.1590/1980-5373-mr-2020-0373

ENGINEERING, CHEMICAL

Universidade de São Paulo

null

Oxidation of AISI 304L and 348 Stainless Steels in Water at High Temperatures

Avelar, Alan Matias

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Oxidation of AISI 304L and 348 stainless steels was investigated in water at 1000 – 1350 °C by TGA, SEM, EDS, and Raman spectroscopy. Linear-Parabolic kinetics and multilayer oxide scales with voids were found for both alloys. Based on the experimental results, AISI 304L presented higher oxidation resistance and higher activation energy. Zircaloy-4 kinetic results were used for validation and performance comparison. In severe accidents conditions, stainless steel might lead to a faster hydrogen production comparing to Zircaloy.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600211&lng=en&tlng=en

30

scielo_articles/scl/1516-1439/S1516-14392020000600211.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Avelar, Alan Matias", "Giovedi, Claudia", "Abe, Alfredo Yuuitiro", "Mourão, Marcelo Breda" ]

null

[ "Stainless steel", "Oxidation", "Hydrogen", "AISI 348", "AISI 304L" ]

null

[ "Universidade de São Paulo", "Universidade de São Paulo", "Instituto de Pesquisas Energéticas e Nucleares" ]

scl/1516-1439/S1516-14392020000600209.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600209

10.1590/1980-5373-mr-2020-0305

ENGINEERING, CHEMICAL

Universidade Federal de Itajubá

null

Coated Surface on Ti-30Ta Alloy for Biomedical Application: Mechanical and in-vitro Characterization

Capellato, Patricia

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Several studies have been carried out to develop new materials for biomedical applications. Material surfaces that present biomimetic morphology like nanotubes or nanofibers that provides nanoscale architectures have been shown to alter cell/biomaterial interactions. The coated surface biomaterial with biocompatible polymers and nanotubes of TiO2 is an alternative to improve osseointegration. The anodization process was performed to obtain nanotubes of TiO2 covering the Ti-30Ta alloy surface and the electrospinning process has been used for producing polymer fibers. Characterization techniques such as scanning electron microscopy (SEM - FEG), X-ray diffraction analysis (X-rays), thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC) and contact angle were used for samples analyses. Adult human adipose-derived stem cells (ADSCs) were used to investigate the cellular response and S. aureus antimicrobial activity on these coated surfaces. The results indicated that both surface modification treatment showed a favorable micro-environment for cells growth and proliferation such as adhesion, viability and morphology which is a desire property for an implant. In addition, the antimicrobial activity study presented both materials with similar growth of S. aureus. So, it can conclude nanotubes and nanofibers can be used at biomedical field and both present similar cell evaluation and antimicrobial activity results.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600209&lng=en&tlng=en

47

scielo_articles/scl/1516-1439/S1516-14392020000600209.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Capellato, Patricia", "Camargo, Samira E. A.", "Silva, Gilbert", "Sachs, Daniela", "Vilela, Filipe Bueno", "Zavaglia, Cecilia A. de C.", "Popat, Ketul C.", "Claro, Ana P.R. Alves" ]

null

[ "Biocompatible polymers", "Titanium alloy", "TiO2 nanotube", "Cell response", "Nanofibers" ]

null

[ "Universidade Federal de Itajubá", "University of Florida", "Universidade Federal de Itajubá", "Universidade Estadual de Campinas", "Colorado State University", "Universidade Estadual Paulista" ]

scl/1516-1439/S1516-14392020000600205.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600205

10.1590/1980-5373-mr-2020-0265

ENGINEERING, CHEMICAL

United Arab Emirates University

null

Ionic Liquid Potential to Recycle Polymeric Waste: An Experimental Investigation

Ahmed, Waleed

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The impact of ionic liquid (IL) solution on the recycling process of polyethylene terephthalate (PET) waste containers used to store drinking water, with a focus on optimizing the added percentage and processing conditions of IL was studied. Characterization using differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FTIR) and nano-indentation tests were performed. Generally, an increase in the degradation temperatures was observed with increasing IL%. Since they were quite comparable, their good thermal stability could be considered. An increase in the hardness was noticed from 0.41 at 0% to 0.45 at a 2% IL solution. A rise in the modulus of elasticity was also observed from 5.5 GPa at 0% to 8 GPa at 2% IL solution. Although there has been some improvement in the properties of the IL blends, limitations such as IL cost and their effective recycling remains a challenge and needs more efforts to fully explore their potential.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600205&lng=en&tlng=en

36

scielo_articles/scl/1516-1439/S1516-14392020000600205.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Ahmed, Waleed", "Khenata, Rabah", "Siraj, Sidra", "Al-Douri, Y." ]

null

[ "Recycling", "PET", "mechanical properties", "ionic liquid" ]

null

[ "United Arab Emirates University", "Mascara University", "United Arab Emirates University", "University of Malaya", "Bahcesehir University" ]

scl/1516-1439/S1516-14392020000600208.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600208

10.1590/1980-5373-mr-2020-0257

ENGINEERING, CHEMICAL

Universidade do Estado do Rio de Janeiro

null

Characterization of Fly Ash and a Protective Coating for Brazilian Thermal Power Plant Boilers

Gomes, Diego de Lima

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Thermoelectric power plants that use mineral coal show high wear in heat exchanger due to the action of several damage mechanisms associated with the impact of hard particles from the residue of burnt coal, the ashes. The employment of coatings should be given into consideration particularly for critical components, which are subject to severe erosive conditions is one of the solutions. However, the choice of material will depend on several factors, including the properties of aggressive ashes. This paper aims to characterize ashes generated by a Brazilian coal-based power plant and a FeCrNbNi-based metallic coating obtained by the electric arc spraying process. No trace of sulfur content was found in fly ashes and it was defined that wear is mainly related to the impact and energy of hard particles are the leading causes of degradation in coal-fired boiler equipment. According to the assessment, applied coating showed (5 ± 2)% by volume of pores and cracks, with 1.6% of oxides after the spraying process and hardness 35% greater than ash particles. Preliminary results in field operation suggest that the material showed relatively low wear compared to the original substrate and showed great applicability in controlling material deterioration for this purpose.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600208&lng=en&tlng=en

56

scielo_articles/scl/1516-1439/S1516-14392020000600208.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Gomes, Diego de Lima", "Cardoso, Bruno Reis", "Furtado, Heloisa Cunha", "Diniz, Marilia Garcia" ]

null

[ "Thermoelectric", "fly ash", "thermal spraying", "metallic coating" ]

null

[ "Universidade do Estado do Rio de Janeiro", "Centro de Pesquisas de Energia Elétrica" ]

scl/1516-1439/S1516-14392020000600207.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600207

10.1590/1980-5373-mr-2019-0687

ENGINEERING, CHEMICAL

Universidad Nacional de Colombia

null

Influence of Si on the Structural, Electrical, and Optical Properties of (Al, Ti, Si)N Films Deposited Via Reactive DC Sputtering

Palacios, A.M. Guzman

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The physical and chemical properties of multifunctional materials have been extensively studied in the last few years especially the mechanical and tribological applications and less attention has taken the electrical and optical properties. Therefore, in this work presents the growth of (Al, Ti, Si)N films deposited on common glass substrates with a maximum thickness of 1024 nm, via reactive DC magnetron sputtering, to analyze the influence of the silicon content on their crystallographic structure, optic and electric behavior. The microstructure of the films was characterized by X-ray diffraction (XRD). The films morphology was evaluated through scanning electronic microscopy (SEM). The optical measurements were carried out by means UV-vis spectroscopy, and the electrical properties were analyzed using a four-point probe. XRD analysis indicated that the films changed from a crystalline phase to an amorphous phase, and the electrical and optical response indicated that the films with higher Si content have l223.6 Ω.cm of resistivity with an energy gap of approximately 1.0 eV and an optical energy gap of 1.5 eV. This electrical property has not been previously reported in these films.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600207&lng=en&tlng=en

37

scielo_articles/scl/1516-1439/S1516-14392020000600207.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Palacios, A.M. Guzman", "Olaya, J.J.", "Alfonso, J.E." ]

null

[ "Multifunctional", "films", "sputtering", "optical and electrical properties" ]

null

[ "Universidad Nacional de Colombia", "Universidad Nacional de Colombia" ]

scl/1516-1439/S1516-14392020000600206.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000600206

10.1590/1980-5373-mr-2020-0180

ENGINEERING, CHEMICAL

Universidade Federal Fluminense

null

Analysis of Microsegregation in Al-Si-Cu Ternary Alloys: Interdependence of Solute Composition at the Solubility Limit during Non-Equilibrium Solidification

Baptista, Luis Antônio de Souza

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Virtually all metals used industrially undergo a solidification process during their production. Depending on the material and its manufacturing process, its physical/mechanical properties are affected to a greater or lesser extent by the microstructure and microsegregation obtained during the phase change. Aluminum casting alloys are good examples of products where this microstructure is vital for obtaining the desired properties. A sequence of experiments to analyze the upward vertical unidirectional solidification with transient heat transfer conditions in Al-Si-Cu ternary alloys was developed in the present work. The experimental results obtained were compared with classical microsegregation models. Discrepancies related to their use for ternary alloys were raised. Since the calculated results by these models do not take into account the influence of one alloying element on the solubility of the other element, disparities were founded between experimental and numerical results. A microsegregation model was proposed based on the solubility limits of the Si in the alloy as a function of the Cu concentration present in the liquid. The model, combined with the concepts of classical microsegregation theory, allows a realistic description of the microsegregation phenomenon. The model showed an excellent agreement between microsegregation profiles of solute experimentally measured and calculated.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000600206&lng=en&tlng=en

37

scielo_articles/scl/1516-1439/S1516-14392020000600206.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Baptista, Luis Antônio de Souza", "Paradela, Késsia Gomes", "Felipe Junior, Paulo", "Sales, Roberto Carlos", "Dantas, Bruno Silva", "Ferreira, Alexandre Furtado" ]

null

[ "Unidirectional solidification", "Al-Si-Cu ternary alloys", "dendritic structure", "microsegregation", "thermal parameters", "modeling" ]

null

[ "Universidade Federal Fluminense" ]

scl/1516-1439/S1516-14392020000500209.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500209

10.1590/1980-5373-mr-2020-0205

ENGINEERING, CHEMICAL

Universidade Estadual Paulista

null

1-3 Castor Oil-Based Polyurethane/PZT Piezoelectric Composite as a Possible Candidate for Structural Health Monitoring

Costa, João Gustavo Leite

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

In this study, we obtained and characterized a piezoelectric composite with 1-3 connectivity from castor oil polyurethane (PUR) and lead zirconate titanate (PZT) rods. Two samples were obtained, one with 15% PZT volume and the other with 34% PZT volume. The ac electrical properties of the 1-3 piezoelectric composite samples demonstrated the frequency-dependence behavior of disordered solids. The piezoelectric coefficient (d33) was greatly influenced by the number of PZT rods and the matrix curing process. The sample with 34% PZT volume showed a higher d33 value, (246 pC/N measured after 30 d of polarization). The composites were evaluated for use in acoustic emission wave sensors for application in structural health monitoring.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500209&lng=en&tlng=en

51

scielo_articles/scl/1516-1439/S1516-14392020000500209.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Costa, João Gustavo Leite", "Rodrigues, Pedro Henrique Ferrarrezi", "Paim, Leonardo Lataro", "Sanches, Alex Otávio", "Malmonge, José Antônio", "Silva, Michael Jones da" ]

null

[ "Piezoelectric composite", "Castor oil polyurethane", "PZT", "Sensor" ]

null

[ "Universidade Estadual Paulista", "Universidade Estadual Paulista", "Universidade Estadual Paulista" ]

scl/1516-1439/S1516-14392020000500208.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500208

10.1590/1980-5373-mr-2020-0252

ENGINEERING, CHEMICAL

Universidade Federal do Tocantins

null

Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels

Souza, Elki C.

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Duplex stainless steels (DSS) are used in off-shore platforms due to their good properties resulting from the combination of two phases, namely austenite and ferrite. Secondary intermetallic phases, such as alpha prime (α´) and sigma (σ), which are harmful, can be formed at temperatures above 400 °C, or by a casting process. This study investigates the formation of sigma phase by thermal cycles running in a dilatometer (800 °C, 850 °C, 900 °C and 1,000 °C) for 1h, and at 850 °C for 3h and 7h. The optical microscopy of the DSS microstructure subjected to 800, 850 and 900 °C for one hour revealed a small fraction of σ phase with nucleation in the contour of ferrite/austenite phases, and tests by ferritoscope indicated a decrease (~4%) in a magnetic fraction (ferrite). However, samples subjected to dilatometric cycles at 850 °C for 3 hours showed an 18% decrease in the magnetic phase and quantitative metallography revealed a 33% fraction of σ phase precipitated in the ferrite phase. Tests conducted at 850 ºC for 7 hours indicated a high fraction of σ phase precipitated (approximately 50%), starting in the grain boundary, austenite/ferrite, and advancing in ferrite grain.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500208&lng=en&tlng=en

24

scielo_articles/scl/1516-1439/S1516-14392020000500208.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Souza, Elki C.", "Bueno, Raiched F.", "Fortulan, Carlos A.", "Rollo, João M. D. A." ]

null

[ "Duplex Stainless Steel (DSS)", "Dilatometer", "Sigma Phase", "Quantitative Metallography", "Ferristoscope", "Intermetallic Phases" ]

null

[ "Universidade Federal do Tocantins", "Universidade de São Paulo", "Universidade de São Paulo" ]

scl/1516-1439/S1516-14392020000500207.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500207

10.1590/1980-5373-mr-2020-0181

ENGINEERING, CHEMICAL

Instituto de Pesquisas Energéticas e Nucleares

null

One-Step Synthesis of AuCu/TiO2 Catalysts for CO Preferential Oxidation

Alencar, Catarine Santos Lopes

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Au/TiO2 (1wt% Au), Cu/TiO2 (1wt% Cu) and AuCu/TiO2 (1wt% AuCu) catalysts with different Au:Cu mass ratios were prepared in one-step synthesis using sodium borohydride as reducing agent. The resulting catalysts were characterized by X-ray diffraction (XRD), X-ray Dispersive Energy (EDX), Transmission Electron Microscopy (TEM) and Temperature Programmed Reduction (TPR) and tested for the preferential oxidation of carbon monoxide (CO-PROX reaction) in H2-rich gases. EDS analysis showed that the Au contents are close to the nominal values whereas for Cu these values are always lower. X-ray diffractograms showed only the peaks of TiO2 phase; no peaks of metallic Au and Cu species or oxides phases were observed. TPR and high-resolution TEM analysis showed that AuCu/TiO2 catalysts exhibited most of Au in the metallic form with particles sizes in the range of 3-5 nm and that Cu was found in the form of oxide in close contact with the Au nanoparticles and well spread over the TiO2 surface. The AuCu/TiO2 catalysts exhibited good performance in the range of 75-100 °C and presented a better catalytic activity when compared to the monometallic ones. A maximum CO conversion of 98.4% with a CO2 selectivity of 47% was obtained for Au0.50Cu0.50/TiO2 catalyst at 100oC.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500207&lng=en&tlng=en

29

scielo_articles/scl/1516-1439/S1516-14392020000500207.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Alencar, Catarine Santos Lopes", "Paiva, Ana Rita Noborikawa", "Silva, Julio Cesar Martins da", "Vaz, Jorge Moreira", "Spinacé, Estevam Vitorio" ]

null

[ "AuCu/TiO2 catalyst", "carbon monoxide", "preferential oxidation", "hydrogen" ]

null

[ "Instituto de Pesquisas Energéticas e Nucleares", "Universidade Federal Fluminense" ]

scl/1516-1439/S1516-14392020000400208.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400208

10.1590/1980-5373-mr-2020-0101

ENGINEERING, CHEMICAL

Hexi University

null

Microstructure and Mechanical Properties of ZA27 Alloy Rheo-Diecasting Process Fabricated by Self-Inoculation Method

Li, Ming

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Semisolid slurry of ZA27 alloy was prepared by Self-inoculation Method (SIM), the effects of isothermal holding parameters on microstructures of rheo-diecasting were researched, and the mechanical properties of ZA27 rheo-diecastings were tested. The results indicate that the dendritic microstructure of ZA27 alloy formed by permanent mold casting can be significantly modified by RDC with SIM, and obtain fine spherical microstructures. After comprehensive consideration, the suitable melt treatment temperature for the ZA27 alloy semisolid processing is 550~560°C. The isothermal holding process of ZA27 alloy slurry has great effect on primary α-Al particles (α1), while has little effect on the microstructure of secondary solidification in the process of thin-walled rheo-diecasting, and the suitable isothermal holding time of semisolid slurry for rheo-diecasting is 3 min. Compared with HPDC, the RDC process can increase the tensile strength of ZA27 alloy by more than 6.9%, with a maximum increase of about 12.5%. The best performance die casting can be obtained when the slurry holding time is 3-5 min.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400208&lng=en&tlng=en

30

scielo_articles/scl/1516-1439/S1516-14392020000400208.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Li, Ming", "Li, Yuandong", "Zhou, Hongwei" ]

null

[ "ZA27 alloy", "Primary particle", "Secondary particle", "Rheo-diecasting", "Mechanical property" ]

null

[ "Hexi University", "Hexi University", "Lanzhou University of Technology" ]

scl/1516-1439/S1516-14392020000400214.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400214

10.1590/1980-5373-mr-2020-0021

ENGINEERING, CHEMICAL

Universidade Tecnológica Federal do Paraná

null

Vitreloy-105 Behavior Under Mutual Wear

Salgado, Felipe Raphael

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Zr-based bulk metallic glasses (BMGs) are widely used as mechanical components due to their excellent properties and high glass-forming ability. However, there is a lack of research concerning the tribological behavior of BMG versus BMG. The sliding characteristics of Vitreloy-105 (Zr52.2Cu17.9Ni14.6Al10Ti5 at.%) were studied in air using a pin-on-disk apparatus equipped for continuous measurement of friction force and without lubrication. The counterface material was the same BMG. The structure, thermal stability, and wear morphology were examined by X-ray diffraction, differential scanning calorimetry, non-contact profilometer, and scanning electron microscopy. For a normal load applied (10.0, 20.4 and 38.2 N) at constant 233 rpm the coefficient of friction ranged from 0.30 to 0.36 at steady state. Average wear rate was more pronounced on the pins under higher load and the predominant wear mechanism observed was adhesive, with presence of peeling-off and micro-cracks accompanied by some grooves and abrasive wear at lower loads.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400214&lng=en&tlng=en

36

scielo_articles/scl/1516-1439/S1516-14392020000400214.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Salgado, Felipe Raphael", "Gonçalves, Janaina Fracaro de Souza", "Mendes, Marcio Andreato Batista", "Campos Neto, Nelson Delfino de", "Oliveira, Marcelo Falcão de" ]

null

[ "Zr-based bulk metallic glasses", "tribological properties", "wear resistance" ]

null

[ "Universidade Tecnológica Federal do Paraná", "Universidade Tecnológica Federal do Paraná", "Universidade de São Paulo", "Colorado School of Mines" ]

scl/1516-1439/S1516-14392020000400213.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400213

10.1590/1980-5373-mr-2020-0210

ENGINEERING, CHEMICAL

Instituto Federal de Educação, Ciência e Tecnologia do Espírito Santo

null

Cold Deformation and Hardness on Superaustenitic Stainless Steel: Evaluation Methods

Avila, Breno Mendes Rabelo

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Superaustenitic stainless steel with high nickel percentage, chromium, molybdenum and nitrogen, has replaced austenitic AISI 304 and 316, mainly in the petrochemical industries, where high toughness, stress corrosion resistance and pitting resistance is suitable. Due to high mechanical stress in the cold deformation manufacturing, residual stresses in the pipes are common. In this case, the possibility of the corrosion process increases. Considering the area reduction after tensile tests, the objective of this study was to evaluate the effects of cold deformation on a superaustenitic steel BS EN 10283 No 14587. The steel was elaborated in an electric induction furnace and the liquid metal was poured out in sand molds. Afterward, samples cut from a specimen submitted to the tensile test were prepared for X-ray diffraction, Vickers hardness measurements, linear polarization and impedance electrochemical tests. The corrosion tests were performed in solution with 3.5% NaCl. The results show that there is a linear increase in hardness and also a decrease in corrosion resistance of the material, with increasing cold deformation. In addition, the cold work reduction was not sufficient to promote strain-induced martensite.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400213&lng=en&tlng=en

28

scielo_articles/scl/1516-1439/S1516-14392020000400213.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Avila, Breno Mendes Rabelo", "Itman Filho, André", "Altoé, João Alberto Fioresi", "Mazini, Jaqueline Polezi", "Oliveira, Pedro Gabriel Bonella de" ]

null

[ "superaustenitic stainless steel", "cold deformation", "corrosion" ]

null

[ "Instituto Federal de Educação, Ciência e Tecnologia do Espírito Santo", "Escola de Engenharia de São Carlos – Universidade de São Paulo" ]

scl/1516-1439/S1516-14392020000400212.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400212

10.1590/1980-5373-mr-2019-0601

ENGINEERING, CHEMICAL

Universidade FEEVALE

null

Influence of the Anodization Process on Zamak 5 Corrosion Resistance

Bianchin, Ana Carolina Viero

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Squeeze casting is the most industrially advantageous process for producing zamak 5 parts. However, this process generates porosity defects in parts, compromising their corrosion resistance. Therefore, this work aims to minimize defects and improve zamak 5 corrosive performance through the anodizing process. For this purpose, zamak 5 was anodized in 300 mol.m-3 oxalic acid and analyzed by ATR-FTIR, SEM, wettability and EIS techniques. The anodizing process promoted the formation of oxalate and oxide layers of Zn and Al, thereby reducing porosity defects. Although the anodized layer has fragile behavior, being porous and permeable, the immersion time of anodized zamak 5 in NaCl forms corrosion products in the alloy that exhibit better protection.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400212&lng=en&tlng=en

33

scielo_articles/scl/1516-1439/S1516-14392020000400212.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Bianchin, Ana Carolina Viero", "Kunst, Sandra Raquel", "Mueller, Luã Tainachi", "Ferreira, Jane Zoppas", "Morisso, Fernando Dal Pont", "Carone, Carlos Leonardo Pandolfo", "Oliveira, Cláudia Trindade" ]

null

[ "Zinc alloys", "Zamak", "Anodizing", "Oxalic acid" ]

null

[ "Universidade FEEVALE", "Universidade Federal do Rio Grande do Sul" ]

scl/1516-1439/S1516-14392020000400211.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400211

10.1590/1980-5373-mr-2020-0201

ENGINEERING, CHEMICAL

Universidade Estadual Paulista

null

Micro-computed Tomography Analysis of the Effect of Immersion Time on Volumetric Stability of Different Endodontic Materials

Torres, Fernanda Ferrari Esteves

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Dental materials should be stable over time. This study investigated volumetric change of the root canal sealers AH Plus, Fill Canal, and Sealapex; and the root-end filling materials Biodentine, IRM, and MTA after different periods of immersion in distilled water. Resin models were manufactured with cavities 3 mm deep. The cavities were filled with the materials and scanned by microcomputed tomography after setting, and after 7 and 30 days immersed in distilled water. Percentages of volumetric changes after 7 and 30 days of immersion were compared by t-test. ANOVA/Tukey tests were used to compare endodontic materials (5% significance level). All root canal sealers had an increase in their volumetric change after 30 days. Among root-end filling materials, only IRM showed difference between the periods. Biodentine showed more volumetric changes than MTA, but both materials kept their volume from 7 to 30 days. In conclusion, the immersion period of endodontic materials may affect their stability.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400211&lng=en&tlng=en

34

scielo_articles/scl/1516-1439/S1516-14392020000400211.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Torres, Fernanda Ferrari Esteves", "Guerreiro-Tanomaru, Juliane Maria", "Bosso-Martelo, Roberta", "Espir, Camila Galletti", "Pinto, Jáder Camilo", "Tanomaru-Filho, Mário" ]

null

[ "Dental materials", "endodontics", "physical properties", "x-ray microtomography" ]

null

[ "Universidade Estadual Paulista", "Universidade Federal da Bahia" ]

scl/1516-1439/S1516-14392020000400210.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400210

10.1590/1980-5373-mr-2019-0350

ENGINEERING, CHEMICAL

Universidade Federal de São João del-Rei

null

Physicochemical Properties of a Solid Fuel from Biomass of Elephant Grass Charcoal (Pennisetum purpureum Schum.) and Recyclable PET and HDPE

Vieira, Sabrina Mara de Macedo

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

In the search for new solid fuels that can mitigate emissions of greenhouse gases and reduce municipal solid waste, it is proposed to produce a solid fuel from elephant grass charcoal (EGC) and blend it with the following binding recyclable materials, polyethylene terephthalate (PET) and high-density polyethylene (HDPE) with the aim of increasing their mechanical strength. Immediate analysis results indicate that there was an increase in volatile material content from 21.18% to 28.02% and a reduction in fixed carbon from 65.00% to 58.40% with the addition of binding agents. The higher heating value of pure charcoal was 5924.16 kcal/kg and there was no significant alteration by adding HDPE, however, with the addition of PET, there was an average reduction of 4.82%. According to the elemental analysis of charcoal, there were no significant amounts of sulphur, but silicon and potassium oxides were predominantly composed followed by aluminium, titanium, magnesium and iron according to the analysis of ashes. The addition of thermoplastic binders allowed producing pellets and it was found that those produced by using HDPE are stronger than those produced with PET.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400210&lng=en&tlng=en

28

scielo_articles/scl/1516-1439/S1516-14392020000400210.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Vieira, Sabrina Mara de Macedo", "Knop, Marcelo de Castro", "Mesquita, Patrícia da Luz", "Baston, Eduardo Prado", "Naves, Fabiano Luiz", "Oliveira, Luiz Fernando Cappa de", "França, Alexandre Bôscaro" ]

null

[ "Charcoal", "recyclable binds", "briquette", "solid fuel" ]

null

[ "Universidade Federal de São João del-Rei", "Universidade Federal de Juiz de Fora" ]

scl/1516-1439/S1516-14392020000400209.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400209

10.1590/1980-5373-mr-2020-0198

ENGINEERING, CHEMICAL

Universidade Federal do Pará

null

Application of a Phase Field Model to Multicomponent Al-Cu-Si alloys

Bezerra, Bruna Norat

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The solidification of metals and alloys and the resulting microstructures, which as a function of thermal and solutal parameters can evolve as planar, cellular and dendritic, are important from a practical point of view, since they strongly influence the properties and quality of the final product. In many practical situations it is impracticable to develop analytical solutions permitting reliable predictions of microstructural growth during unsteady-state solidification conditions. The Phase Field method has become very popular and effective in modeling complex solid/liquid interfaces due to its ability to simulate the interface kinetics and the formation and evolution of different morphologies along the solidification process. In this work, a numerical analysis of the microstructural evolution during the transient solidification of dilute alloys of the Al-Cu-Si system is developed, which uses a phase-field approach for the simulation of ternary alloys. The phase-field, energy and solute concentration equations were numerically solved for the correspondent ternary system, varying the mesh parameters, temperature and alloy composition. The analysis performed were confronted with existing theoretical models and the results obtained are in agreement with the solidification theory.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400209&lng=en&tlng=en

25

scielo_articles/scl/1516-1439/S1516-14392020000400209.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Bezerra, Bruna Norat", "Ferreira, Diego José Sacramento", "Ferreira, Alexandre Furtado", "Garcia, Amauri", "Ferreira, Ivaldo Leão" ]

null

[ "Phase field method", "Aluminum alloys", "Multicomponent alloys", "Microstructural development" ]

null

[ "Universidade Federal do Pará", "Universidade Federal Fluminense", "Universidade de Campinas" ]

scl/1516-1439/S1516-14392020000400207.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400207

10.1590/1980-5373-mr-2020-0110

ENGINEERING, CHEMICAL

Universidade Federal Fluminense

null

The Effect of the Cooling Rate on the Microstructure and Microsegregation: An Experimental and Numerical Investigation of Solidification in Hypoperitectic Cu − 20 wt.% Sn Alloy

Paradela, Késsia Gomes

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Hypoperitectic Cu − 20 wt.% Sn alloy was solidified under different cooling rates and solidification growths using directional solidification system. The effects of cooling rate and solidification growth on the microsegregation profiles and tertiary dendritic arm spacing (λ3) were experimentally investigated along the casting. A mathematical model known as phase-field was applied to simulate microstructure and microsegregation during solidification in system Cu-Sn liquid. In this paper the applicability of the phase-field model to the solidification problem in a real alloy system was systematically explored. Microsegregation profiles and realistic dendritic structures were obtained using the phase-field model. The results calculated by phase-field model show various solidification features consistent with our experiment. The calculated tertiary dendritic arm spacing (λ3) and microsegregation profiles were compared with experimental values from directional solidification system. Since the calculated microsegregation profiles using the equilibrium partition coefficient (keq) can yielded discrepancies from the experimental results, an effective partition coefficient (kef) as a function of solidification growth, is proposed in phase-field model, showing a good agreement with the experimental data for any case examined.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400207&lng=en&tlng=en

37

scielo_articles/scl/1516-1439/S1516-14392020000400207.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Paradela, Késsia Gomes", "Garção, Wysllan Jefferson Lima", "Baptista, Luis Antônio de Souza", "Sales, Roberto Carlos", "Oliveira, Vânia Cristina de", "Ferreira, Alexandre Furtado" ]

null

[ "Cu-Sn alloy", "solidification", "dendritic microstructure", "microsegregation", "phase-field model" ]

null

[ "Universidade Federal Fluminense", "Instituto Federal do Rio de Janeiro" ]

scl/1516-1439/S1516-14392020000400216.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400216

10.1590/1980-5373-mr-2019-0666

ENGINEERING, CHEMICAL

Universidad Nacional Autónoma de México

null

Fractal and Conventional Analysis of Cu Content Effect on the Microstructure of Al-Si-Cu-Mg Alloys

Casas, Bertha Y.

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

This work analyzes the effect of Cu additions on the microstructure of quaternary alloys Al-6Si-7Mg-xCu (x= 3, 5 and 7 wt.%) produced by conventional metallurgy. Microstructural modifications were studied using Optical Microscopy (OM), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), focusing on second phases identification and quantification. Conventional image analyses were developed measuring the total percentage of second phases, and individually for each phase determining its equivalent diameter, shape factor, roundness and aspect ratio; while fractal analyses were carried out complementarily through fractal dimension measurements for the whole microstructure and for individual phases. Compression tests were also carried out. SEM and XRD results revealed that second phases were eutectic Si, Mg2Si, Al2Cu and Al5Cu2Mg8Si6 (Q). The increase in Cu content led to higher quantities of these phases, mainly Al2Cu, which was barely present for the alloy with the lowest Cu content. Morphologies of second phases depended on Cu content, being present as eutectic, block like, finely dispersed or primary particles. The combination of conventional and fractal parameters provided a useful tool for comparatively analyze microstructural modifications and second phases features. It was also found that the compressive behavior of the alloys depended on the resulting microstructures.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400216&lng=en&tlng=en

30

scielo_articles/scl/1516-1439/S1516-14392020000400216.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Casas, Bertha Y.", "Carranza, Juan C.", "Figueroa, Ignacio A.", "González, Jose G.", "Hernáncdez, Orlando", "Béjar, Luis", "Aguilar, Claudio", "Alfonso, Ismeli" ]

null

[ "Al alloys", "microstructure", "mechanical properties", "SEM", "fractal", "second phases" ]

null

[ "Universidad Nacional Autónoma de México", "Universidad Nacional Autónoma de México", "Universidad Nacional Autónoma de México", "Universidad Michoacana de San Nicolás Hidalgo", "Universidad Técnica Federico Santa María" ]

scl/1516-1439/S1516-14392020000400206.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400206

10.1590/1980-5373-mr-2020-0197

ENGINEERING, CHEMICAL

Universidade Estadual de Londrina

null

Diphenyltetrazole Modified Bacterial Cellulose Film: Considerations on Heterogeneous Modification and Bioconjugation

Birkheur, Simone

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Understanding chemical reactions in bacterial cellulose (BC) films is important to control the insertion of biomolecules that can improve their biomedical properties. Diphenyltetrazole molecules are able to react with tiols under UV irradiation and has been useful for immobilize proteins on different materials. In this work, we show the functionalization of a BC film with diphenyltetrazole and subsequent attempts of conjugation of the bovine serum albumin (BSA) to it. Diphenyltetrazole was synthesized in two steps, and functionalization of it with BC was carried out under ultrasound irradiation. Spectroscopic analysis of the film by UV–Vis and FTIR confirmed the success of the reaction. Attempts to conjugate BSA to the modified cellulose film by photoclick reaction failed under these conditions. Although this methodology is important in the conjugation of biomolecules, we understand that its application in cellulosic materials in heterogeneous phase is disadvantaged due to the half-life of the unstable intermediate and the biomolecule's access to it.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400206&lng=en&tlng=en

31

scielo_articles/scl/1516-1439/S1516-14392020000400206.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Birkheur, Simone", "Laureto, Edson", "Fernandes, Ricardo Vignoto", "Tischer, Cesar", "Butera, Anna Paola", "Ribeiro-Viana, Renato M." ]

null

[ "bacterial cellulose", "bioconjugation", "photoclick" ]

null

[ "Universidade Estadual de Londrina", "Universidade Estadual de Londrina", "Universidade Estadual de Londrina", "Universidade Tecnológica Federal do Paraná" ]

scl/1516-1439/S1516-14392020000400205.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400205

10.1590/1980-5373-mr-2020-0162

ENGINEERING, CHEMICAL

Institute for Advanced Studies

null

A Comparative Study of Abbreviated Heat Treatments for SAE 4130 Steel After Laser Welding

Mansur, Raquel Alvim de Figueiredo

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract It was verified that SAE 4130 steel plates crack when laser beam welded at room temperature (RT). To overcome this problem, this work proposes a high temperature (HT) laser welding in order to reduce the residual stresses and create a bainitic structure instead of a martensitic one. A conventional post-welding heat treatment (PWHT) had been used as a comparison for HT. The centerline crack disappeared after a heat treatment of both in-situ (HT) or after inserting in a furnace (PWHT) at 500 °C for 10 minutes. The finite element analyses indicated a residual stress reduction from 163.70 to 3.72 MPa in the fusion zone (FZ) of the welds from RT to HT. The hardness obtained in FZ depends on the thermal cycle induced microstructure of the welds as 400 HV, 340 HV and 250 HV, for martensite (RT), tempered martensite (PWHT) and bainite (HT) micro-constituents. The proposed in-situ high-temperature laser beam welding method proved its usefulness to solve the center crack issue in SAE 4130 joints.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400205&lng=en&tlng=en

28

scielo_articles/scl/1516-1439/S1516-14392020000400205.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Mansur, Raquel Alvim de Figueiredo", "Ferreira, Caroline Cristine de Andrade", "Atílio, Isabela", "Carvalho, Sheila Medeiros de", "Braga, Vagner", "Siqueira, Rafael Humberto de Mota", "Lima, Milton Sergio Fernandes de" ]

null

[ "Laser beam welding", "SAE 4130 steel", "heat treatment", "hardening" ]

null

[ "Institute for Advanced Studies" ]

scl/1516-1439/S1516-14392020000400204.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400204

10.1590/1980-5373-mr-2020-0120

ENGINEERING, CHEMICAL

Universidade Federal de Santa Catarina

null

Effect of Cutting Parameters in Machining Force, Surface Texture and Chips Morphology Obtained in Turning of Sintered Self-Lubricating Composites

Ebersbach, Felipe Gustavo

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract This work presents a study on effect of cutting parameters in force, texture and chips morphology obtained during the turning of a self-lubricating sintered composite. The tests were performed varying the cutting speed (vc = 100 and 200 m/min), feed (f = 0.1 and 0.2 mm), depth of cut (ap = 0.5 and 1 mm), as well as the materials manufacturing route in single pressing (SP) and double pressing (DP). The variation in the cutting parameters influenced the components of the machining force. The cutting, feed and passive force were approximately 10%, 10% e 25% higher, respectively, for DP materials. The turning process generated surfaces with values of maximum height (Sz) between 28.3 to 10.8 μm, Kurtosis (Sku) > 3 and Skewness (Ssk) < 0.3. The chip type obtained was segmented and the chip thickness ratio was influenced by the variation of the cutting parameters and the materials manufacturing route.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400204&lng=en&tlng=en

42

scielo_articles/scl/1516-1439/S1516-14392020000400204.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Ebersbach, Felipe Gustavo", "Builes, Sara Diaz", "Dorneles, Caroline Francisco", "Schroeter, Rolf Bertrand", "Binder, Cristiano", "Klein, Aloísio Nelmo", "Mello, José Daniel Biasoli de" ]

null

[ "Turning", "Machining force", "Surface texture", "Chips", "Self-lubricating composites" ]

null

[ "Universidade Federal de Santa Catarina", "Universidade Federal de Santa Catarina", "Universidade Federal de Uberlândia" ]

scl/1516-1439/S1516-14392020000400203.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400203

10.1590/1980-5373-mr-2020-0073

ENGINEERING, CHEMICAL

Universidade Federal do Paraná

null

Vibration Control Using Multilayer Piezoelectric Actuators: Towards Chatter Supression in Turning Operations

Venter, Giuliana Sardi

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Chatter causes poor surface quality and damage to tools in machining. Therefore, strategies for chatter monitoring and reduction are constantly under investigation. Among these strategies, the use of piezoelectric layers embedded in the tool-holder as sensors/actuators for control strategies had been proposed for improving the stability limit reducing the system vibration. Nevertheless, actuators implemented using a single piezoelectric layer may fail to suppress chatter due to its limited actuation power. A method for assembling a series multilayer piezoelectric actuator is then proposed, which can provide a better performance and ultimately suppress chatter in turning operations. This actuator is used with passive and active control and the system response is investigated using frequency response functions. Two fixation conditions are tested to analyze the robustness of the control strategies. The results show that the use of a multilayer piezoelectric actuator made it possible for a greater reduction in vibration amplitude in the chatter frequency.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400203&lng=en&tlng=en

24

scielo_articles/scl/1516-1439/S1516-14392020000400203.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Venter, Giuliana Sardi", "Silva, Maíra Martins da" ]

null

[ ": Internal turning", "Passive Control", "Active Control", "Stability Limit" ]

null

[ "Universidade Federal do Paraná", "Universidade de São Paulo" ]

scl/1516-1439/S1516-14392020000400202.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400202

10.1590/1980-5373-mr-2020-0010

ENGINEERING, CHEMICAL

Universidade de São Paulo

null

Vat Photopolymerization Additive Manufacturing Resins: Analysis and Case Study

Lovo, João Fiore Parreira

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Additive manufacturing processes have been developed over the last decades, especially vat photopolymerization (VP) processes, due to its simplicity and speed. The objective of this paper is to characterize commercial VP resins widely used for technical applications. Thus, test specimens were printed by Digital Light Processing and subjected to tensile, compression, flexural, hardness, and inorganic composition analyses. The resin with the highest resistance and hardness (containing 0.6 vol% of inorganics load) reached 53 MPa in tension, 110 MPa in compression, 79 MPa in bending, and 82.3 Shore D, which is comparable to injected polymers. A case study was made, replacing the injected gears of a reducer by printed ones and comparing the finite element analysis with resin properties. The characterization and case study results encourage the expansion of VP processes in the manufacturing of products in several industries and service sectors, as well as the development of new composite resins.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400202&lng=en&tlng=en

44

scielo_articles/scl/1516-1439/S1516-14392020000400202.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Lovo, João Fiore Parreira", "Camargo, Italo Leite de", "Erbereli, Rogério", "Morais, Mateus Mota", "Fortulan, Carlos Alberto" ]

null

[ "3D printing", "FEM", "photopolymerization", "DLP" ]

null

[ "Universidade de São Paulo", "Instituto Federal de Educação, Ciência e Tecnologia de São Paulo" ]

scl/1516-1439/S1516-14392020000400201.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400201

10.1590/1980-5373-mr-2019-0697

ENGINEERING, CHEMICAL

Universidade Federal de Minas Gerais

null

Thermal Fatigue Analysis of Hot Forging Closed Dies

Vianello, Pedro Ivo

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The aim of this work is to develop a numerical subroutine for the commercial finite element method software QFORM VX 8.1.4 capable of predicting, simultaneously, regions of closed dies which are prone to thermal fatigue as well as the number of cycles required for thermal fatigue cracking. The numerical subroutine was based on Manson (thermal fatigue) and Coffin-Manson (number of cycles) equations. Hot forging of AISI 1045 grinding balls using AISI H13 closed dies was performed and the numerical and experimental results were compared. The findings indicated that after forging 66 grinding balls, the numerical model achieved steady state for the temperature inside the die. After forging 600 grinding balls, both the experimental and numerical results showed that the regions of the dies subjected to the highest thermal gradient were prone to thermal fatigue. In addition to that, the numerically predicted values for the onset of thermal cracking were consistent with the experimental results: 517 and 600 cycles, respectively.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400201&lng=en&tlng=en

16

scielo_articles/scl/1516-1439/S1516-14392020000400201.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Vianello, Pedro Ivo", "Santos, Anderson Junior dos", "Abrão, Alexandre Mendes", "Magalhães, Frederico de Castro" ]

null

[ "Hot Forging", "thermal fatigue", "finite element method", "AISI H13 steel" ]

null

[ "Universidade Federal de Minas Gerais", "Universidade Federal de Minas Gerais" ]

scl/1516-1439/S1516-14392020000400215.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400215

10.1590/1980-5373-mr-2020-0023

ENGINEERING, CHEMICAL

Universidade Federal Fluminense

null

An Experimental Investigation of Continuous Casting Process: Effect of Pouring Temperatures on the Macrosegregation and Macrostructure in Steel Slab

Quinelato, Fernando Paulucio

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The solidification control is of extreme importance, because it strongly affects the final casting quality sanity. The structure obtained is generally not homogeneous and gives rise to great variations in composition, with position at small and large scales, which is known as segregation. An understanding of the way segregation occurs in continuous casting is of great importance for steels and in designing post-casting processes. As-cast structures are responsible the reduction in both scale and extension of segregation, because mass transport is dependent on the time required to diffuse a solute over a characteristic distance, e.g., the dendrite spacing that the characterizes the solidification structure. In this work, the effect of pouring temperature in steel slabs on the continuous casting processes are systematically investigated. Relationships between pouring temperature (PT) and center macrosegregation was qualitatively examined. Photomicrographs of specimen taken from transverse sections of steel slabs, shows that macrosegregation is strongly affected by pouring temperature (PT). For solute of carbon, phosphorus and sulfur, has been shown that the pouring temperature (PT) has a significant role on the resulting macrosegregation profiles, while that the elements as such silicon, manganese and aluminum, the said thermal parameter seems not able to affect its macrosegregation profiles. This is due to the fact that the solutes with lower partition coefficients favors segregation during the continuous casting process. It is shown for considered steels, the pouring temperature (PT) influences the position of the columnar to equiaxed transition (CET). Experimental results show that the end of the columnar region is abbreviated when lower pouring temperatures is used in continuous casting process. One can observe that as the pouring temperature (PT) increase in continuous casting process, the secondary dendritic arm spacing (λ2) increase, i.e., the dendritic morphology became coarsen.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400215&lng=en&tlng=en

30

scielo_articles/scl/1516-1439/S1516-14392020000400215.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Quinelato, Fernando Paulucio", "Garção, Wysllan Jefferson Lima", "Paradela, Késsia Gomes", "Sales, Roberto Carlos", "Baptista, Luis Antônio de Souza", "Ferreira, Alexandre Furtado" ]

null

[ "Continuous casting process", "solidification", "pouring temperature", "segregation and carbon steel" ]

null

[ "Universidade Federal Fluminense", "Instituto Federal do Rio de Janeiro" ]

scl/1516-1439/S1516-14392020000400217.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400217

10.1590/1980-5373-mr-2020-0013

ENGINEERING, CHEMICAL

Universidade Federal de Santa Catarina

null

Experimental Investigation of the Sawn Surface of Monocrystalline Silicon Cut by Endless Diamond Wire Sawing

Costa, Erick Cardoso

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The aim of this study was to investigate the influence of the cutting parameters on monocrystalline silicon cut by diamond wire sawing. The sawn surface was analyzed in terms of surface morphology, surface roughness, material removal mechanism and residual stress (by Raman spectroscopy). The surface morphology exhibited evidence of both material removal mechanisms: the brittle mode and the ductile mode. The surface roughness increased with a high vf, which promoted the formation of craters on the sawn surface. On applying a higher vc, the surface roughness reduced, since this favored the formation of damage-free grooves. The Raman spectrum showed evidence of different residual crystalline phases on the sawn surface, which confirms the material removal mechanisms. An increase in vf, for the same vc, caused at reduction in the compressive stress, since the brittle mode predominated as the material removal mechanism. Maintaining vf constant and increasing vc results in higher compressive stress, caused by plastic deformation of the silicon during chip formation.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400217&lng=en&tlng=en

23

scielo_articles/scl/1516-1439/S1516-14392020000400217.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Costa, Erick Cardoso", "Santos, Caroline Piesanti dos", "Xavier, Fabio Antonio", "Weingaertner, Walter Lindolfo" ]

null

[ "Diamond wire sawing", "Monocrystalline silicon", "Brittle-to-ductile transition", "Residual stress", "Phase transformation" ]

null

[ "Universidade Federal de Santa Catarina" ]

scl/1516-1439/S1516-14392020000500206.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500206

10.1590/1980-5373-mr-2020-0264

ENGINEERING, CHEMICAL

Universidade Federal do Rio Grande do Sul

null

Constitutive Modelling of High Temperature Flow Behaviour for a Low Carbon High Silicon Bainitic Steel

Ivaniski, Thiago Marques

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract It is well recognized the importance of the rheological characterization for the development of the steel in thermomechanical treatments, especially for the mechanical properties improvement of bainitic steels in subsequent hot forging optimization. Therefore, the plastic strain behaviour of a low carbon high silicon bainitic steel was studied through isothermal compression tests using a thermomechanical simulator at temperatures of 1123 K – 1423 K and strain rates of 0.1 – 5 s-1. Arrhenius equation was used to obtain the constitutive constants, which represents the material behaviour of flow stress in high temperature. Besides, work hardening, dynamic recovery, and the JMAK model in the dynamic recrystallization (DRX) of the steel parameters were determined. The second part of this research compared two proposed modified models from the literature, which showed the differences in modelled flow curves behaviour when they are applied for high strain levels. The flow curves were modelled in high strain levels for further implementation in numerical simulation, thus allowing an adjustment of parameters in hot forming processes for this bainitic steel. The proposed models presented an agreement with experimental values. However, only the Avrami equation to DRX showed the dynamic recovery mechanism in high strain levels, which has represented physical behaviour during the thermomechanical process.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500206&lng=en&tlng=en

26

scielo_articles/scl/1516-1439/S1516-14392020000500206.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Ivaniski, Thiago Marques", "Souza, Tomaz Fantin de", "Épp, Jérémy", "Rocha, Alexandre da Silva" ]

null

[ "Flow Curves Modelling", "Dynamic revorery and Dynamic recrystallization Kinetics", "Bainitic Steels" ]

null

[ "Universidade Federal do Rio Grande do Sul", "Instituto Federal de Educação", "Leibniz-Institut für Werkstofforientierte Technologien", "University of Bremen" ]

scl/1516-1439/S1516-14392020000400226.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000400226

10.1590/1980-5373-mr-2020-0166

ENGINEERING, CHEMICAL

Universidade Federal de Itajubá

null

Nanoparticles of FeNbO4 Produced by Microwave Assisted Combustion Reaction: A Potential Technology for the Treatment of Wastewater

Andrade, F. V. de

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Iron(III) niobate, FeNbO4, was synthesized for the first time by microwave-assisted combustion reaction between Fe(NO3)3.9H2O and NH4[NbO(C2O4)2(H2O)2](H2O) in the presence of NH4NO3 and Urea {O=C(NH2)2}. Experiments of X-ray powder diffraction revealed a small crystallite size for this material, 16 nm, and the results of MEV showed that it forms agglomerates with diameters between 80 and 180 nm with spherical shapes. HRTEM images revealed that the material is formed by clusters of particles with a diameter near 20 nm. A surface area of 40 m2g-1 was determined by experiments of specific surface area (SSA). The FeNbO4 induced the decomposition of H2O2, forming radicals that, in turn, discoloured Indigo dye Carmine (IC) a solution. The results showed that this niobate was able to degrade 55% of the initial solution in the presence of H2O2 after 360 minutes of reaction time.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000400226&lng=en&tlng=en

37

scielo_articles/scl/1516-1439/S1516-14392020000400226.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Andrade, F. V. de", "Costa, C. F.", "Freitas, M. R. de", "Cabral, A. C. T.", "Barros, N. M.", "Lima, G. M. de" ]

null

[ "iron(III) niobate", "synthesis by microwave-assisted combustion", "advanced oxidative processes", "environmental remediation", "organic contaminants" ]

null

[ "Universidade Federal de Itajubá", "Universidade Federal de Itajubá", "Universidade Federal de Minas Gerais" ]

scl/1516-1439/S1516-14392020000500204.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392020000500204

10.1590/1980-5373-mr-2019-0496

ENGINEERING, CHEMICAL

King Fahd University of Petroleum and Minerals

null

Corrosion Behavior of Spark Plasma Sintered Alumina and Al2O3-SiC-CNT Hybrid Nanocomposite

Al-Ashwan, Z.H.

2,020

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The use of ceramic-based materials has become more common in many applications because of their unique characteristics and properties. Design of alumina hybrid nanocomposites achieved by incorporating two nanoreinforcements, with different morphologies and/or attributes, such as CNTs and SiC, is a new approach that has been adopted to enhance the properties of alumina. The microstructural, mechanical, electrical, and thermal properties of Al2O3-SiC-CNT hybrid nanocomposites were investigated and reported in the literature. However, the corrosion behavior was not considered. The present paper reports the electrochemical corrosion behavior of pure Al2O3 and Al2O3-5SiC-2CNT hybrid nanocomposite in acidic (2.34M HCl) and alkaline (6.5M NaOH) environments at room temperature. Ball milling (BM) and spark plasma sintering (SPS) were used for preparation of samples. The microstructure of sintered samples was investigated through field emission scanning electron microscopy (FE-SEM). Potentiodynamic polarization (PDP) technique was used to investigate the corrosion behavior. The corrosion rate of the Al2O3-5SiC-2CNT nanocomposite increased 96 and 178% in HCl and NaOH solution, respectively, compared to alumina. Possible corrosion mechanisms and factors effecting corrosion were discussed.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500204&lng=en&tlng=en

62

scielo_articles/scl/1516-1439/S1516-14392020000500204.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Al-Ashwan, Z.H.", "Hayat, U.", "Toor, I.H.", "Hassan, Syed Fida", "Saheb, N." ]

null

[ "Alumina", "hybrid ceramic nanocomposites", "spark plasma sintering", "electrochemical corrosion" ]

null

[ "King Fahd University of Petroleum and Minerals", "King Fahd University of Petroleum and Minerals" ]

scl/1516-1439/S1516-14392022000100386.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392022000100386

10.1590/1980-5373-mr-2022-0275

ENGINEERING, CHEMICAL

Universidade Federal de São Carlos

null

Evaluation of 6000 Al Alloys for Application in Chassis of Electric Vehicles

Saldanha, Felipe Escher

2,022

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract The market for electric vehicles is growing, seen as the best alternative to replace internal combustion-powered vehicles. Recent developments in electric vehicles have allowed them to reach a level of performance, comfort, and safety that enables them to compete with traditional vehicles. However, several studies are directed towards increasing the autonomy of these vehicles, aiming at weight reduction of structural components. Aluminum alloys are increasingly being chosen to produce structural elements, due to their low density and suitable properties. The 6000 Al alloys are often used in chassis and bodywork. In view of this, this work proposes a comparison of 6000 series alloys, by means of thermodynamic (using Thermo-Calc®) and property computations (Ansys® Granta EduPack and Selector) to select the best alloys considering application properties, processability, and environmental impact. It was observed that the T6 heat-treated alloys presented better mechanical properties, but, on the other hand, they have more impact on the environment. As such, the 6010-T6 alloy was classified as the best alloy regarding performance, the 6061-T4 alloy the best in terms of processability, and the 6009-T4 alloy presented the lowest environmental impact. The 6111-T4 alloy was highlighted as the alloy showing the best balance between the examined properties.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392022000100386&lng=en&tlng=en

19

scielo_articles/scl/1516-1439/S1516-14392022000100386.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Saldanha, Felipe Escher", "Sousa, Sarah de Albuquerque", "Gouveia, Guilherme Lisboa de", "Dwek, Mauricio", "Spinelli, José Eduardo" ]

null

[ "Electric Vehicle", "6000 Alloys", "Industry 4.0", "Environmental Impact" ]

null

[ "Universidade Federal de São Carlos", "Universidade Federal de São Carlos", "Ansys" ]

scl/1516-1439/S1516-14392021000200208.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200208

10.1590/1980-5373-mr-2020-0313

ENGINEERING, CHEMICAL

Universidade Estadual de Campinas

null

Thixoforming of an Al-Si-Zn-Mg Alloy - Thermodynamic Characterization, Microstructural Evolution and Rheological Behavior

Dantas, André Victor Rodrigues

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Al-Si-Zn-Mg quaternary alloys represent a potential range of feedstock's for semisolid processing (SSM) that combine the advantages of the thixoforming process with the possibility of heat treatment to improve mechanical performance. In this work, the suitability of the Al-5wt%Si-5wt%Zn-0.5wt%Mg alloy for use in thixoforming was assessed by thermodynamic characterization and by an analysis of its microstructural evolution and rheological behavior. Thermodynamic analysis was performed by numerical simulation and by application of the differentiation method to Differential Scanning Calorimetry (DSC) curves for heating cycles up to 700 °C at 5 and 25 °C/min. Microstructural evolution during partial melting at 594 °C for 0, 30, 60 and 90 s and the corresponding rheological behavior were analyzed. The findings indicate good agreement between the thermodynamic behavior predicted by DSC and Calculation of Phase Diagrams (CALPHAD) and the data obtained from semisolid forging. Although the alloy has a coarse microstructure (GSmax = 200 μm), its rheological behavior is appropriate for thixoforming (σmax = 1.06 MPa and μmax = 1.79x104 Pa.s), indicating that the microstructure only plays a secondary role in determining viscosity when enough liquid (fl = 0.63) is present in the slurry to enhance the flow. The alloy is suitable for use as raw material for semisolid processing.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200208&lng=en&tlng=en

46

scielo_articles/scl/1516-1439/S1516-14392021000200208.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Dantas, André Victor Rodrigues", "Brollo, Gabriela Lujan", "Tamayo, Daimer Velasquez", "Zoqui, Eugênio José" ]

null

[ "Thixoforming", "semisolid materials", "Calphad", "Al-Si-Zn-Mg alloy", "microstructure", "rheology" ]

null

[ "Universidade Estadual de Campinas", "Universidad de Oriente" ]

scl/1516-1439/S1516-14392021000300212.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000300212

10.1590/1980-5373-mr-2020-0361

ENGINEERING, CHEMICAL

Universidade de São Paulo

null

Reduction of Magnesium Corrosion Rate by PMMA-co-PMAA Films

Gonsalves, Tayara C.

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Magnesium is an important base material for non-permanent implants, even though its corrosion rate in the human body is usually elevated for most applications. In order to reduce that rate, polymer coatings can be a better option than heavy-metal containing Mg alloys. In this work, random copolymers of PMMA and PMAA were synthesized and used for coating pure Mg by simply immersing Mg coupons into a diluted copolymer solution. It has been shown by SEM analysis and quantitative adsorption analysis that the copolymers have adsorbed onto the Mg surface. All the coated materials presented a lower corrosion rate than the uncoated Mg, reaching close to 100% reduction for most of the copolymer up to 6 hours of testing. The copolymers with 5, 8 and 13% of PMAA in their composition showed the best performances as corrosion controllers.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000300212&lng=en&tlng=en

22

scielo_articles/scl/1516-1439/S1516-14392021000300212.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Gonsalves, Tayara C.", "Freitas, Bruno X. de", "Nunes, Carlos A.", "Florenzano, Fábio H." ]

null

[ "Magnesium", "Biomaterials", "PMMA-co-PMAA", "Corrosion", "Polymer Coating" ]

null

[ "Universidade de São Paulo" ]

scl/1516-1439/S1516-14392021000100222.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000100222

10.1590/1980-5373-mr-2020-0470

ENGINEERING, CHEMICAL

Universidade de São Paulo, Escola Politécnica

null

A Short Review on Ultra-High-Strength Maraging Steels and Future Perspectives

Fonseca, Daniela Passarelo Moura da

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Maraging steels are among the highest strength steels commercially available. Despite being relatively rare and expensive, they may present a yield strength around 3 GPa and are indispensable for various applications. In the present paper, several aspects will be reviewed related to maraging steels including a brief history of its development, microstructure and acting hardening mechanisms, loss of toughness with the tensile strength increase, resistance to oxidation, and corrosion, nitriding behavior, and future perspectives.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000100222&lng=en&tlng=en

71

scielo_articles/scl/1516-1439/S1516-14392021000100222.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Fonseca, Daniela Passarelo Moura da", "Feitosa, Ana Larissa Melo", "Carvalho, Leandro Gomes de", "Plaut, Ronald Lesley", "Padilha, Angelo Fernando" ]

null

[ "maraging steels", "microstructure", "mechanical properties", "oxidation" ]

null

[ "Universidade de São Paulo, Escola Politécnica", "Centro Universitário Adventista de São Paulo" ]

scl/1516-1439/S1516-14392021000200205.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200205

10.1590/1980-5373-mr-2020-0501

ENGINEERING, CHEMICAL

Arab American University

null

Structural, Optical and Electrical Properties of Bi1.5Zn0.92Nb1.5-6x/5WxO6.92 Pyrochlore Ceramics

Qasrawi, A. F.

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Herein, the structural, morphological, compositional, optical, electrical and dielectric properties of Bi1.5Zn0.92Nb1.5-6x/5WxO6.92 (BZN) solid solutions are reported. Tungsten substituted BZN ceramics which are fabricated by the solid state reaction technique exhibited solubility limits at substitution level below x=0.18. Remarkable engineering in the structural, optical, electrical and dielectric properties of the pyrochlore ceramics is achieved via W substitution. Namely, shrinkage in both of the lattice parameters and in the energy band gap accompanied with decrease in the microstrain, in the dielectric constant and in the electrical resistivity is observed upon increasing the W content below the solubility limit. The increase in the W content in the BZN ceramics enhances the densification of the pyrochlore and leads to higher light absorbability and larger crystallites growth. The temperature dependent electrical resistivity measurements has also shown that the pyrochlore exhibit thermal stability below 380 K.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200205&lng=en&tlng=en

30

scielo_articles/scl/1516-1439/S1516-14392021000200205.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Qasrawi, A. F.", "Abdalghafour, Mays A.", "Mergen, A." ]

null

[ "Bi1.5Zn0.92Nb1.5-6x/5WxO6.92", "ceramics", "XRD", "resistivity", "band gap" ]

null

[ "Arab American University", "Atilim University", "Marmara University" ]

scl/1516-1439/S1516-14392021000200204.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200204

10.1590/1980-5373-mr-2020-0277

ENGINEERING, CHEMICAL

Instituto Federal de Educação Ciência e Tecnologia do Rio Grande do Sul

null

New Method to Distinguish Adhesion and Cohesion Stresses in Metal/Polymer Composites

Utumi, Marcos Vinicius

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract This study aims at presenting a new analysis method for adhesive (interfacial) and cohesive (bulk) failures in aluminum (Al) and high-density polyethylene (HDPE) sandwich composites. The samples were submitted to tensile strength tests, according to ASTM C297 so as to obtain the pull-off stresses. The delaminated aluminum surfaces were analyzed with SEM/EDS (Scanning Electronic Microscopy with Energy Dispersive Scanning). The images were calculated using a genetic algorithm (GA), where the areas with cohesive and adhesive failures were identified by the presence or absence of organic compounds. The proposed method also uses the data from the pull-off tests to determine the stress values of adhesion and cohesion separately. Applying the new method, the mean stress of cohesion was 4.17 MPa, and for adhesion it was 0.57 MPa. Thus, it was possible to distinguish and calculate the failure stresses applied to metal/polymer composites.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200204&lng=en&tlng=en

24

scielo_articles/scl/1516-1439/S1516-14392021000200204.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Utumi, Marcos Vinicius", "Corso, Leandro Luís", "Gasparin, Alexandre Luís" ]

null

[ "sandwich composite", "adhesion and cohesion strength", "genetic algorithm" ]

null

[ "Instituto Federal de Educação Ciência e Tecnologia do Rio Grande do Sul", "Universidade de Caxias do Sul" ]

scl/1516-1439/S1516-14392021000200203.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200203

10.1590/1980-5373-mr-2020-0485

ENGINEERING, CHEMICAL

Universidade Federal de Campina Grande

null

Refractory Ceramics of Clay and Alumina Waste

Silva, Valmir José da

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

Abstract Refractory ceramics were produced from clays and alumina waste. Specimens were shaped by uniaxial pressing, subjected to thermal analysis by dilatometry and heat-treated in a conventional furnace at 1300 and 1400ºC, applying a heating rate of 5ºC/min and a dwell time of 2 and 3 hours at the maximum temperature. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and physicomechanical properties. The dilatometric analysis before heat treatment indicated that the formulation containing the largest amount of fluxing oxides presented the highest linear shrinkage. The XRD analysis revealed that mullite was the major phase and needle shaped crystals typical of mullite obtained from clay minerals were observed by SEM. The increase in firing temperature and dwell time at the maximum temperature improved the physicomechanical properties of the specimens. The thermal expansion coefficient (TEC) in the range of 25 to 1000ºC varied from 6.2 to 6.9 x 10-6°C-1.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200203&lng=en&tlng=en

48

scielo_articles/scl/1516-1439/S1516-14392021000200203.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Silva, Valmir José da", "Taveira, Salvador K. A.", "Silva, Karina R.", "Neves, Gelmires A.", "Lira, Hélio L.", "Santana, Lisiane N. L." ]

null

[ "Clays", "alumina waste", "refractory ceramics" ]

null

[ "Universidade Federal de Campina Grande" ]

scl/1516-1439/S1516-14392021000200202.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200202

10.1590/1980-5373-mr-2020-0362

ENGINEERING, CHEMICAL

Universidade Federal de Pernambuco

null

Evaluation of the Multi-Structural Potential of Ni-Co/SiC Nanocomposite Coatings Electrodeposited in API 5L X80 Steel

Pereira, Roseana F. da C.

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

The use of nanocomposite coatings on carbon steel has been very promising. In this paper, the formation mechanism of multilayer of Ni-Co/SiC nanocomposite coating electrodeposited in API 5L X80 steel was investigated. The coatings were obtained by galvanostatic deposition technique using a single bath and a single cathodic current density value. The results showed a variation in morphology and chemical composition of the coatings both on the surface and along the cross-section at all time conditions tested, confirming the functional gradient of the coating. The formation of the Ni-Co/SiC nanocomposite coating occurred through the multilayer deposition mechanism, with compositions mostly alternated between Ni and Co. The preferred orientation of the plane (220) and phase structure FCC remained constant on the surface of all the obtained samples. It was observed that the coating became more compact in the region located closer to the substrate, where an increase in micro-hardness was observed.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200202&lng=en&tlng=en

36

scielo_articles/scl/1516-1439/S1516-14392021000200202.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Pereira, Roseana F. da C.", "Oliveira, Edkarlla S. D. de", "Lima, Maria Alice G. de A.", "Urtiga Filho, Severino L." ]

null

[ "Ni-Co/SiC nanocomposite", "functionally graded coatings", "multiple layers", "galvanostatic deposition", "API 5L X80 steel" ]

null

[ "Universidade Federal de Pernambuco", "Universidade Federal de Pernambuco" ]

scl/1516-1439/S1516-14392021000200201.xml

en

research-article

Materials Research

1980-5373

SciELO Brazil

ABM, ABC, ABPol

S1516-14392021000200201

10.1590/1980-5373-mr-2020-0232

ENGINEERING, CHEMICAL

Universitas Negeri Malang

null

Fabrication of New Fe3O4/PVA/(C6H7O6Na)n Nanohybrid Ferrogels for Antibacterial Applications

Taufiq, Ahmad

2,021

null

This work is licensed under a Creative Commons Attribution 4.0 International License.

null

New Fe3O4/polyvinyl alcohol (PVA)/sodium alginate (C6H7O6Na)n nanohybrid ferrogels for antibacterial applications were fabricated. The crystal and molecular structures along with optical and magnetic properties of the prepared samples were characterized. The antibacterial activity of the ferrogels against Bacillus subtilis and Escherichia coli was investigated using the agar dilution method. X-ray diffraction analysis showed that the Fe3O4/PVA comprised a PVA amorphous phase and a spinel-structured Fe3O4 crystalline phase. The Fe3O4/PVA crystallite size was 7.5–9.9 nm and the scanning electron micrographs showed that the Fe3O4/PVA agglomerated. The ferrogels were superparamagnetic with saturation magnetizations from 14.8 × 10−3 to 82.1 × 10−3 emu/g. The absorption of the ferrogels showed a bathochromic effect, accompanied by an increase in the bandgap from 2.09 to 2.18 eV with increasing Fe3O4 content in the ferrogels. The ferrogels demonstrated new potency as antibacterial agents against B. subtilis and E. coli, where their antibacterial performance increased with increasing Fe3O4 content.

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000200201&lng=en&tlng=en

40

scielo_articles/scl/1516-1439/S1516-14392021000200201.xml

scielo.br

scl

[ "ENGINEERING, CHEMICAL", "MATERIALS SCIENCE, MULTIDISCIPLINARY", "METALLURGY & METALLURGICAL ENGINEERING" ]

[ "Taufiq, Ahmad", "Iswatin, Anggra D.", "Saputro, Rosy E.", "Yogihati, Chusnana I.", "Hidayat, Nurul", "Diantoro, Markus", "", "" ]

null

[ "Fe3O4/PVA/(C6H7O6Na)n", "nanohybrid", "ferrogels", "superparamagnetic", "antibacterial agent" ]

null

[ "Universitas Negeri Malang", "Universitas Negeri Surabaya" ]