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Activation of dislocations in Mg with solute Y
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作者 alireza maldar Leyun Wang +4 位作者 Boyu Liu Wenjun Liu Zhaohui Jin Bijin Zhou Xiaoqin Zeng 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第3期1045-1053,共9页
Mg-Y cast alloy shows excellent ductility(elongation to failure>15%)compared with pure Mg and commercial Mg cast alloys.By monitoring the microstructure evolution during an in situ tensile test of a Mg-2.5 wt%Y all... Mg-Y cast alloy shows excellent ductility(elongation to failure>15%)compared with pure Mg and commercial Mg cast alloys.By monitoring the microstructure evolution during an in situ tensile test of a Mg-2.5 wt%Y alloy,we identify the activation of prismatic<c>slip,which is rare in Mg.Synchrotron X-ray micro-beam Laue diffraction(μ-Laue)and transmission electron microscopy revealed the morphology of prismatic<c>slip bands and individual<c>dislocations.Density functional theory and molecular dynamics calculations indicate that solute Y can significantly reduce the stacking fault energy(SFE)along<c>direction on prismatic plane in Mg lattice and thus facilitate the nucleation of<c>dislocations during deformation.The presence of free<c>dislocations in the Mg lattice can also lead to nucleation of{10–12}twins even under unfavorable geometric conditions. 展开更多
关键词 ALLOY MICROSTRUCTURE DUCTILITY
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Investigation of the alloying effect on deformation behavior in Mg by Visco-Plastic Self-Consistent modeling 被引量:8
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作者 alireza maldar Leyun Wang +1 位作者 Gaoming Zhu Xiaoqin Zeng 《Journal of Magnesium and Alloys》 SCIE 2020年第1期210-218,共9页
Alloying elements can drastically alter the deformation behavior of Mg.In the present work,Visco-Plastic Self-Consistent(VPSC)modeling was employed to investigate the effect of alloying elements on Mg’s tensile behav... Alloying elements can drastically alter the deformation behavior of Mg.In the present work,Visco-Plastic Self-Consistent(VPSC)modeling was employed to investigate the effect of alloying elements on Mg’s tensile behavior,in particular the relative activity of different slip and twinning modes.Mg-0.47 wt.%Ca,Mg-2 wt.%Nd,and AZ31 extruded alloys were deformed by micro-tensile tests in a scanning electron microscope(SEM).Texture and grain size measured by electron backscatter diffraction(EBSD)were used as the input for VPSC.After parameter optimization,the VPSC model successfully reproduced the stress-strain curve of each alloy.Simulation results indicate that the slip/twinning activity in the three alloys are different.Mg-0.47 wt.%Ca shows strong extrusion texture,and prismatic slip was quite active during its tensile deformation.In contrast,Mg-2 wt.%Nd shows weak extrusion texture,and basal slip was dominant.This alloy also developed more twinning activity than the other two alloys.AZ31 shows strong extrusion texture similar as Mg-0.47 wt.%Ca,but prismatic slip was less active in it.The slip/twinning activity revealed by the VPSC model can explain the difference in the tensile behavior of the three alloys. 展开更多
关键词 Mg alloys Crystal plasticity SLIP EBSD Tensile test
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Dynamic recrystallization and precipitation in high manganese austenitic stainless steel during hot compression 被引量:3
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作者 Amir Momeni Shahab Kazemi +1 位作者 Golam Ebrahimi alireza maldar 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2014年第1期36-45,共10页
Dynamic recrystallization and precipitation in a high manganese austenitic stainless steel were investigated by hot compression tests over temperatures of 950-1150~C at strain rates of 0.001 s-1-1 s-1. All the flow cu... Dynamic recrystallization and precipitation in a high manganese austenitic stainless steel were investigated by hot compression tests over temperatures of 950-1150~C at strain rates of 0.001 s-1-1 s-1. All the flow curves within the studied deformation regimes were typ- ical of dynamic recrystallization. A window was constructed to determine the value of apparent activation energy as a function of strain rate and deformation temperature. The kinetics of dynamic recrystallization was analyzed using the Avrami kinetics equation. A range of apparent activation energy for hot deformation from 303 kJ/mol to 477 kJ/mol is obtained at different deformation regimes. Microscopic characterization confirms that under a certain deformation condition (medium Zener-Hollomon parameter (Z) values), dynamic recrystalliza- tion appears at first, but large particles can not inhibit the recrystallization. At low or high Z values, dynamic recrystallization may occur be- fore dynamic precipitation and proceeds faster. In both cases, secondary phase precipitation is observed along prior austenite grain bounda- ries. Stress relaxation tests at the same deformation temperatures also confirm the possibility of dynamic precipitation. Unexpectedly, the Avrami's exponent value increases with the increase of Z value. It is associated with the priority of dynamic recrystallization to dynamic precipitation at higher Z values. 展开更多
关键词 austenitic stainless steel hot deformation dynamic recrystallization PRECIPITATION activation energy
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Dislocation behavior in a polycrystalline Mg-Y alloy using multi-scale characterization and VPSC simulation 被引量:2
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作者 Bijin Zhou Leyun Wang +6 位作者 Jinhui Wang alireza maldar Gaoming Zhu Hailong Jia Peipeng Jin Xiaoqin Zeng Yanjun Li 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第3期87-98,共12页
In this study,the dislocation behavior of a polycrystalline Mg-5Y alloy during tensile deformation was quantitatively studied by an in-situ tensile test,visco-plastic self-consistent(VPSC)modeling,and transmission ele... In this study,the dislocation behavior of a polycrystalline Mg-5Y alloy during tensile deformation was quantitatively studied by an in-situ tensile test,visco-plastic self-consistent(VPSC)modeling,and transmission electron microscopy(TEM).The results of the in-situ tensile test show that<a>dislocations contribute to most of the deformation,while a small fraction of<c+a>dislocations are also activated near grain boundaries(GBs).The critical resolved shear stresses(CRSSs)of different dislocation slip systems were estimated.The CRSS ratio between prismatic and basal<a>dislocation slip in the Mg-Y alloy(~13)is lower than that of pure Mg(~80),which is considered as a major reason for the high ductility of the alloy.TEM study shows that the<c+a>dislocations in the alloy have high mobility,which also helps to accommodate the deformation near GBs. 展开更多
关键词 Mg-Y alloy Dislocation behavior Deformation mechanisms Critical resolved shear stress
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