B. Straumal, A. Kilmametov, A. Mazilkin, Olga Kogtenkova Kogtenkova, B. Baretzky, A. Korneva, P. Ziȩba
Severe plastic deformation (SPD) can induce various phase transformations. After a certain strain, the dynamic equilibrium establishes between defects production by an external force and their relaxation (annihilation). The grain size, hardness, phase composition etc. in this steady-state does not depend on the initial state of a material and is, therefore, equifinal. In this review we discuss the competition between precipitation and dissolution of precipitates, amorphization and (nano)crystallization, SPD-induced accelerated mass-transfer, allotropic and martensitic transitions and formation of grain boundary phases.
{"title":"DIFFUSIVE AND DISPLACIVE PHASE TRANSFORMATIONS UNDER HIGH PRESSURE TORSION","authors":"B. Straumal, A. Kilmametov, A. Mazilkin, Olga Kogtenkova Kogtenkova, B. Baretzky, A. Korneva, P. Ziȩba","doi":"10.12776/ams.v25i4.1368","DOIUrl":"https://doi.org/10.12776/ams.v25i4.1368","url":null,"abstract":"Severe plastic deformation (SPD) can induce various phase transformations. After a certain strain, the dynamic equilibrium establishes between defects production by an external force and their relaxation (annihilation). The grain size, hardness, phase composition etc. in this steady-state does not depend on the initial state of a material and is, therefore, equifinal. In this review we discuss the competition between precipitation and dissolution of precipitates, amorphization and (nano)crystallization, SPD-induced accelerated mass-transfer, allotropic and martensitic transitions and formation of grain boundary phases.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48525766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Bui, Khanh-Van Nguyen, B. Duong, Thang Hong Le, Bang Thi Le, S. Said
Quaternary chalcogenide Cu2ZnSnS4 is a potential candidate for thermoelectric (TE) application due to a number of advantages including containing only non-toxic and abundant elements, high Seebeck coefficient and low thermal conductivity. In this study, Cu2ZnSnS4 was synthesized using mechanical alloying method from Cu, Zn, Sn and S powders. In order to study the effect of milling duration on the formation of Cu2ZnSnS4, different milling duration of 2, 4, 12 and 16 h were investigated. As the results, Cu2ZnSnS4 was started to form after milling for 12 h. The formation of Cu2ZnSnS4 was completed after 16 h of milling. In addition, Cu2ZnSnS4 nanoparticles were obtained after 16 h of milling with the distribution mostly in the range of 50 - 60 nm.
{"title":"SYNTHESIS OF Cu2ZnSnS4 BY MECHANICAL ALLOYING METHOD FOR THERMOELECTRIC APPLICATION","authors":"L. Bui, Khanh-Van Nguyen, B. Duong, Thang Hong Le, Bang Thi Le, S. Said","doi":"10.12776/ams.v25i3.1311","DOIUrl":"https://doi.org/10.12776/ams.v25i3.1311","url":null,"abstract":"Quaternary chalcogenide Cu2ZnSnS4 is a potential candidate for thermoelectric (TE) application due to a number of advantages including containing only non-toxic and abundant elements, high Seebeck coefficient and low thermal conductivity. In this study, Cu2ZnSnS4 was synthesized using mechanical alloying method from Cu, Zn, Sn and S powders. In order to study the effect of milling duration on the formation of Cu2ZnSnS4, different milling duration of 2, 4, 12 and 16 h were investigated. As the results, Cu2ZnSnS4 was started to form after milling for 12 h. The formation of Cu2ZnSnS4 was completed after 16 h of milling. In addition, Cu2ZnSnS4 nanoparticles were obtained after 16 h of milling with the distribution mostly in the range of 50 - 60 nm.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42415959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Springback is a common phenomenon in sheet metal forming, in which the material undergoes an elastic recovery as applied loads are removed. Springback causes the forming shape to deviate from the intended design geometry. This phenomenon, which can be influenced by several factors, effects on both bending angle and bending curvature. The aim of this study is to determine the influence of different tool radius and the gap between punch and die on springback in bending of DP980 Advanced High-Strength Steels (AHSS) sheet. Experimental studies are combined with FEM method in commercial ABAQUS software to determine the bending angle after springback. To predict springback in bending process, the material properties are defined by Ludwik - Hollomon law, combined with the Hill’48 criterion. Experimental results are in good agreement with numerical simulations in case of bending in the rolling direction.
{"title":"EFFECT OF SPRINGBACK IN DP980 ADVANCED HIGH STRENGTH STEEL ON PRODUCT PRECISION IN BENDING PROCESS","authors":"Hu Le, D. Vu, Phuong Thi Doan, Kien Trung Le","doi":"10.12776/ams.v25i3.1306","DOIUrl":"https://doi.org/10.12776/ams.v25i3.1306","url":null,"abstract":"Springback is a common phenomenon in sheet metal forming, in which the material undergoes an elastic recovery as applied loads are removed. Springback causes the forming shape to deviate from the intended design geometry. This phenomenon, which can be influenced by several factors, effects on both bending angle and bending curvature. The aim of this study is to determine the influence of different tool radius and the gap between punch and die on springback in bending of DP980 Advanced High-Strength Steels (AHSS) sheet. Experimental studies are combined with FEM method in commercial ABAQUS software to determine the bending angle after springback. To predict springback in bending process, the material properties are defined by Ludwik - Hollomon law, combined with the Hill’48 criterion. Experimental results are in good agreement with numerical simulations in case of bending in the rolling direction.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46203415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matías Sosa, Alejandro Sepulveda Buitrago, A. Picasso
The 45Ni-35Cr-Nb alloy, commonly known as ET45 micro, produced in the form of centrifugally cast tubes, was studied by means of optical microscopy after aging treatments at 1073 and 1173 K for different times. A description of M23C6 secondary carbides precipitation phenomenon was made as a function of time. The analysis after using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model showed that the secondary carbide precipitation occurs in a single stage. It was found that this phenomenon, which is assisted by diffusion, has an activation energy of 196 kJ/mol.
{"title":"STUDY OF M23C6 PRECIPITATION IN A 45Ni-35Cr-Nb ALLOY","authors":"Matías Sosa, Alejandro Sepulveda Buitrago, A. Picasso","doi":"10.12776/ams.v25i3.1312","DOIUrl":"https://doi.org/10.12776/ams.v25i3.1312","url":null,"abstract":"The 45Ni-35Cr-Nb alloy, commonly known as ET45 micro, produced in the form of centrifugally cast tubes, was studied by means of optical microscopy after aging treatments at 1073 and 1173 K for different times. A description of M23C6 secondary carbides precipitation phenomenon was made as a function of time. The analysis after using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model showed that the secondary carbide precipitation occurs in a single stage. It was found that this phenomenon, which is assisted by diffusion, has an activation energy of 196 kJ/mol.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48938171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, the influence of rare earth (RE) on the microstructure and mechanical properties of austenitic high manganese steel (HMnS) Mn15Cr2V were investigated. The results showed that the microstructure, hardness and impact strength of RE modification sample is finer and better than non-modified sample. Under the effect of impact load, the hardness and the depth of the work-hardening layer of the modified steel was higher than that of the non-modified steel, thereby, the value of microhardness in the surface of the modified sample was 420 HV while it was only 395 HV in the non-modified sample. The value of the impact strength of the modified sample was up to 132 J/cm2 compared to the non-modified sample is only 115 J/cm2. Moreover, after impact load, the austenite nanoparticles had been found out on the surface of this steel, this is the cause of the increasing of mechanical properties in this steel.
{"title":"INFLUENCE OF RARE-EARTH ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HIGH MANGANESE STEEL UNDER IMPACT LOAD","authors":"N. Nguyen, N. Nguyen, K. M. Pham","doi":"10.12776/ams.v25i3.1309","DOIUrl":"https://doi.org/10.12776/ams.v25i3.1309","url":null,"abstract":"In this paper, the influence of rare earth (RE) on the microstructure and mechanical properties of austenitic high manganese steel (HMnS) Mn15Cr2V were investigated. The results showed that the microstructure, hardness and impact strength of RE modification sample is finer and better than non-modified sample. Under the effect of impact load, the hardness and the depth of the work-hardening layer of the modified steel was higher than that of the non-modified steel, thereby, the value of microhardness in the surface of the modified sample was 420 HV while it was only 395 HV in the non-modified sample. The value of the impact strength of the modified sample was up to 132 J/cm2 compared to the non-modified sample is only 115 J/cm2. Moreover, after impact load, the austenite nanoparticles had been found out on the surface of this steel, this is the cause of the increasing of mechanical properties in this steel.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41715612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Setyana, M. Mahardika, Sutiyoko Sutiyoko, S. Suyitno
Shape and direction of gating in centrifugal casting affected the microstructures and defects. The purpose of this research was to determine the effects of gating shape and direction in centrifugal casting toward porosity, density, roughness, and microstructures on the artificial lumbar disc model. The main shapes of gating were circular and rectangular cross-section. The circular cross-section gating was used for two different directions of artificial lumbar discs; vertical, and horizontal. Furthermore, the rectangular cross-section design consisted of three different directions; oblique clockwise, oblique counter-clockwise and perpendicular towards the mold. The rotational mold was conducted at a speed of 60 rpm. The results showed that the rectangular cross-section gating with the oblique direction same with the rotation of the mold produced artificial lumbar disc model that had the smallest porosity area among the other directions. It was the best gating design among the others which had the smallest porosity area (0,68%), highest density (4,517 g/cm3), and smoothest roughness (8,76 µm). In the sub-surface, the microstructure of α-case was formed. The thickness and hardness of the α-case in this design were 50-100 µm and 760 VHN, respectively. Hence, the rectangular cross-section gating with the oblique direction same with the rotation of the mold was appropriate to be applied in the manufacture of an artificial lumbar disc model.
{"title":"EFFECT OF GATING SHAPE AND DIRECTION DURING CENTRIFUGAL CASTING OF ARTIFICIAL LUMBAR DISC MODEL OF CP-TI","authors":"L. Setyana, M. Mahardika, Sutiyoko Sutiyoko, S. Suyitno","doi":"10.12776/ams.v25i3.1315","DOIUrl":"https://doi.org/10.12776/ams.v25i3.1315","url":null,"abstract":"Shape and direction of gating in centrifugal casting affected the microstructures and defects. The purpose of this research was to determine the effects of gating shape and direction in centrifugal casting toward porosity, density, roughness, and microstructures on the artificial lumbar disc model. The main shapes of gating were circular and rectangular cross-section. The circular cross-section gating was used for two different directions of artificial lumbar discs; vertical, and horizontal. Furthermore, the rectangular cross-section design consisted of three different directions; oblique clockwise, oblique counter-clockwise and perpendicular towards the mold. The rotational mold was conducted at a speed of 60 rpm. The results showed that the rectangular cross-section gating with the oblique direction same with the rotation of the mold produced artificial lumbar disc model that had the smallest porosity area among the other directions. It was the best gating design among the others which had the smallest porosity area (0,68%), highest density (4,517 g/cm3), and smoothest roughness (8,76 µm). In the sub-surface, the microstructure of α-case was formed. The thickness and hardness of the α-case in this design were 50-100 µm and 760 VHN, respectively. Hence, the rectangular cross-section gating with the oblique direction same with the rotation of the mold was appropriate to be applied in the manufacture of an artificial lumbar disc model.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46875468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soumia Hamza, Z. Boumerzoug, Elhadj Raouache, F. Delaunois
This work is a contribution study of the heat-affected zone in the real welded joint of stainless steel 304L. This zone was compared to the heat-affected zone obtained by using a thermal cycle simulation of welding. This experimental technique is based on thermal cycle simulation of welding by rapid heating and cooling treatments of the base metal in a specific simulation equipment. The samples were analyzed by scanning electron microscopy equipped with energy dispersive X-ray, and microhardness measurements. Microstructures and mechanical properties of the simulated heat affected zone were also determined. Thermal cycle simulation technique has revealed more details on the microstructure and the mechanical behavior of the heat-affected zone.
{"title":"SIMULATED HEAT AFFECTED ZONE IN WELDED STAINLESS STEEL 304L","authors":"Soumia Hamza, Z. Boumerzoug, Elhadj Raouache, F. Delaunois","doi":"10.12776/ams.v25i3.1290","DOIUrl":"https://doi.org/10.12776/ams.v25i3.1290","url":null,"abstract":"This work is a contribution study of the heat-affected zone in the real welded joint of stainless steel 304L. This zone was compared to the heat-affected zone obtained by using a thermal cycle simulation of welding. This experimental technique is based on thermal cycle simulation of welding by rapid heating and cooling treatments of the base metal in a specific simulation equipment. The samples were analyzed by scanning electron microscopy equipped with energy dispersive X-ray, and microhardness measurements. Microstructures and mechanical properties of the simulated heat affected zone were also determined. Thermal cycle simulation technique has revealed more details on the microstructure and the mechanical behavior of the heat-affected zone.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42819545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Petrík, P. Blaško, Andrea Vasilňaková, P. Demeter, P. Futas
The aim of the submitted work is to study the influence of applied loads ranging from 0.09807 N to 0.9807 N on measured values of micro-hardness of heat treated aluminum alloy 6082. The influence of applied load on a measured value of micro-hardness was evaluated by Meyer’s index n, PSR method and by Analysis of Variance (ANOVA). The influence of the load on the measured value of micro-hardness is statistically significant and the relationship between the applied load and micro-hardness manifests the moderate reverse ISE. As the temperature of the solution treatment rises, the YS/UTS ratio and also Meyer’s index n, measured and “true hardness“ increase. On the other hand, its effect on the plastic properties of the alloy is ambiguous.
本文的目的是研究0.09807 N ~ 0.9807 N的外加载荷对6082热处理铝合金显微硬度测量值的影响。采用Meyer 's指数n、PSR法和方差分析(ANOVA)评价外加载荷对显微硬度测量值的影响。载荷对显微硬度测量值的影响具有统计学意义，载荷与显微硬度之间的关系表现为中度逆ISE。随着固溶处理温度的升高，YS/UTS比、Meyer指数n、实测硬度和“真硬度”均增大。另一方面，它对合金塑性性能的影响是不明确的。
{"title":"INDENTATION SIZE EFFECT OF HEAT TREATED ALUMINUM ALLOY","authors":"J. Petrík, P. Blaško, Andrea Vasilňaková, P. Demeter, P. Futas","doi":"10.12776/ams.v25i3.1310","DOIUrl":"https://doi.org/10.12776/ams.v25i3.1310","url":null,"abstract":"The aim of the submitted work is to study the influence of applied loads ranging from 0.09807 N to 0.9807 N on measured values of micro-hardness of heat treated aluminum alloy 6082. The influence of applied load on a measured value of micro-hardness was evaluated by Meyer’s index n, PSR method and by Analysis of Variance (ANOVA). The influence of the load on the measured value of micro-hardness is statistically significant and the relationship between the applied load and micro-hardness manifests the moderate reverse ISE. As the temperature of the solution treatment rises, the YS/UTS ratio and also Meyer’s index n, measured and “true hardness“ increase. On the other hand, its effect on the plastic properties of the alloy is ambiguous.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43898537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Nguyen, Tu Anh Dao, H. M. Le, K. Dang, M. Nanko
Transparent MgAl2O4 ceramic could be found in a wide range of applications for both military and civil sector due to its high melting point, good mechanical properties, small refractive index (1.71) and its ability to allow light in range from UV to mid-IR to pass through. In the present work, transparent MgAl2O4 were fabricated from metal nitrates via two steps. Firstly, the MgAl2O4 nanopowder was synthesized via solution combustion synthesis from the metal nitrates. Secondly, the powder was then consolidated by Pulsed Electric Current Sintering (PECS) technique to fabricate transparent ceramic. XRD patterns of the obtained powder showed the peaks of only MgAl2O4 phase. Besides, the atomic compositions of magnesium, aluminium and oxygen determined by EDX analysis were approximately corresponded to 1:2:4 of the molecular formula of MgAl2O4. After deagglomerating for 48 hours using soft ball-milling, the powder had the average particle of 27 nm. Transparent MgAl2O4 samples, which were sintered with two-step sintering mode of 1050oC/60 minutes-1400oC/20 minutes, permitted the transmission of visible and infrared light with the transmittance up to 80%, Vickers hardness of 14.2 GPa, and fracture toughness of 1.1 MPa.m1/2. The results are a critical step toward fabrication of high-quality transparent ceramics from metal nitrates.
{"title":"FABRICATION OF TRANSPARENT MgAl2O4 SPINEL CERAMICS BY PECS PROCESSING OF COMBUSTION - SYTHESIZED NANOPOWDERS","authors":"Y. Nguyen, Tu Anh Dao, H. M. Le, K. Dang, M. Nanko","doi":"10.12776/ams.v25i3.1313","DOIUrl":"https://doi.org/10.12776/ams.v25i3.1313","url":null,"abstract":"Transparent MgAl2O4 ceramic could be found in a wide range of applications for both military and civil sector due to its high melting point, good mechanical properties, small refractive index (1.71) and its ability to allow light in range from UV to mid-IR to pass through. In the present work, transparent MgAl2O4 were fabricated from metal nitrates via two steps. Firstly, the MgAl2O4 nanopowder was synthesized via solution combustion synthesis from the metal nitrates. Secondly, the powder was then consolidated by Pulsed Electric Current Sintering (PECS) technique to fabricate transparent ceramic. XRD patterns of the obtained powder showed the peaks of only MgAl2O4 phase. Besides, the atomic compositions of magnesium, aluminium and oxygen determined by EDX analysis were approximately corresponded to 1:2:4 of the molecular formula of MgAl2O4. After deagglomerating for 48 hours using soft ball-milling, the powder had the average particle of 27 nm. Transparent MgAl2O4 samples, which were sintered with two-step sintering mode of 1050oC/60 minutes-1400oC/20 minutes, permitted the transmission of visible and infrared light with the transmittance up to 80%, Vickers hardness of 14.2 GPa, and fracture toughness of 1.1 MPa.m1/2. The results are a critical step toward fabrication of high-quality transparent ceramics from metal nitrates.","PeriodicalId":44511,"journal":{"name":"Acta Metallurgica Slovaca","volume":null,"pages":null},"PeriodicalIF":1.0,"publicationDate":"2019-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47365536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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