The effect of Gd,Ce and Y elements on texture,recrystallization and mechanical properties of Mg–1.5Zn alloys was investigated.The results show that the addition of Gd,Ce and Y elements in Mg–1.5Zn alloy,which rolled...The effect of Gd,Ce and Y elements on texture,recrystallization and mechanical properties of Mg–1.5Zn alloys was investigated.The results show that the addition of Gd,Ce and Y elements in Mg–1.5Zn alloy,which rolled at 450℃ and subsequently annealed at 350℃ for 1h,can effectively weaken and modify the basal texture,characterized by the splitting basal pole toward to transverse direction,leading to the yield and tensile strength,the highest along the rolling direction and the lowest along the transverse direction.Besides,the unique basal texture contributes to the significant improvement of elongation at room temperature.Electron back scattering diffraction(EBSD)analysis indicated that the non-basal texture in Mg–1.5Zn–0.2RE alloys can be attributed to obstructive effect of static recrystallization and the non-basal orientation grains nucleation near pre-existing grain boundaries during annealing.Specially,the Mg–1.5Zn–0.2Gd sheet exhibits much excellent plasticity with the elongation of 27%than Mg–1.5Zn–0.2Ce and Mg–1.5Zn–0.2Y alloys,resulting from the less and smaller second phase of MgZnGd.展开更多
The heat-affected zone(HAZ) of electron beam welded(EBW) joint normally undergoes a unique heat-treating process consisting of rapid temperature rising and dropping stages, resulting in temperature-gradient in HAZ as ...The heat-affected zone(HAZ) of electron beam welded(EBW) joint normally undergoes a unique heat-treating process consisting of rapid temperature rising and dropping stages, resulting in temperature-gradient in HAZ as a function of the distance to fusion zone(FZ). In the current work,microstructure, elements distribution and crystallographic orientation of three parts(near base material(BM) zone, mid-HAZ and near-FZ) in the HAZ of Ti-6Al-4V alloy were systematically investigated. The microstructure observation revealed that the microstructural variation from near-BM to near-FZ included the reduction of primary α(αp) grains, the increase of transformed β structure(βt) and the formation of various α structures. The rim-α, dendritic α and abnormal secondary α(αs) colonies formed in the mid-HAZ, while the "ghost" structures grew in the near-FZ respectively. The electron probe microanalyzer(EPMA) and electron back-scattered diffraction(EBSD) technologies were employed to evaluate the elements diffusion and texture evolution during the unique thermal process of welding. The formation of the various α structures in the HAZ were discussed based on the EPMA and EBSD results. Finally, the nanoindentation hardness of "ghost" structures was presented and compared with nearby βt regions.展开更多
High-grade non-oriented silicon steel with higher permeability and lower core loss has become the pursed target with the rapid developnient of electrical machines.The effects of rare-earth(RE)element on recrystallizat...High-grade non-oriented silicon steel with higher permeability and lower core loss has become the pursed target with the rapid developnient of electrical machines.The effects of rare-earth(RE)element on recrystallization texture in RE-doped Fe-3.1 wt.%Si-1.2 wt.%Al non-oriented silicon steel were investigated by macro-and micro-texture analyses.Nonlinear variation of recrystallization texture with RE element content was observed.In the competition among main recrystallization texture components,favorable{113}<361>and X fiber(<001>//ND)are strengthened and unfavorable y fiber is evidently decreased by the addition of RE element,whereas the effect of RE element is reversed by excess RE element.The recrystallization texture development is determined by RE-affected nucleation and grain growth in terms of grain boundary migration related to segregation and inclusion.The properly inhibited grain boundary mobility can promote favorable recrystallization texture by the improved nucleation and efficient grain growth.展开更多
In this study,a reduced-order crystal plasticity finite element(CPFE)model was developed to study the effects of the microstructural morphology and crystallographic texture on the mechanical anisotropy of selective la...In this study,a reduced-order crystal plasticity finite element(CPFE)model was developed to study the effects of the microstructural morphology and crystallographic texture on the mechanical anisotropy of selective laser melted(SLMed)Ti-6Al-4V.First,both hierarchical and equiaxed microstructures in columnar prior grains were modeled to examine the influence of the microstructural morphology on mechanical anisotropy.Second,the effects of crystallographic anisotropy and textural variability on mechanical anisotropy were investigated at the granular and representative volume element(RVE)scales,respectively.The results show that hierarchical and equiaxed CPFE models with the same crystallographic texture exhibit the same mechanical anisotropy.At the granular scale,the significance of crystallographic anisotropy varies with different crystal orientations.This indicates that the present SLMed Ti-6Al-4V sample with weak mechanical anisotropy resulted from the synthetic effect of crystallographic anisotropies at the granular scale.Therefore,combinations of various crystallographic textures were applied to the reduced-order CPFE model to design SLMed Ti-6Al-4V with different mechanical anisotropies.Thus,the crystallographic texture is considered the main controlling variable for the mechanical anisotropy of SLMed Ti-6Al-4V in this study.展开更多
The mechanical properties of an extruded Mg-10Gd sample, specifically designed for vascular stents, are crucial for predicting its behavior under service conditions. Achieving homogeneous stresses in the hoop directio...The mechanical properties of an extruded Mg-10Gd sample, specifically designed for vascular stents, are crucial for predicting its behavior under service conditions. Achieving homogeneous stresses in the hoop direction, essential for characterizing vascular stents, poses challenges in experimental testing based on standard specimens featuring a reduced cross section. This study utilizes an elasto-visco-plastic self-consistent polycrystal model(ΔEVPSC) with the predominant twinning reorientation(PTR) scheme as a numerical tool, offering an alternative to mechanical testing. For verification, various mechanical experiments, such as uniaxial tension, compression, notched-bar tension, three-point bending, and C-ring compression tests, were conducted. The resulting force vs. displacement curves and textures were then compared with those based on the ΔEVPSC model. The computational model's significance is highlighted by simulation results demonstrating that the differential hardening along with a weak strength differential effect observed in the Mg-10Gd sample is a result of the interplay between micromechanical deformation mechanisms and deformation-induced texture evolution. Furthermore, the study highlights that incorporating the axisymmetric texture from the as-received material incorporating the measured texture gradient significantly improves predictive accuracy on the strength in the hoop direction. Ultimately, the findings suggest that the ΔEVPSC model can effectively predict the mechanical behavior resulting from loading scenarios that are impossible to realize experimentally, emphasizing its valuable contribution as a digital twin.展开更多
文摘The effect of Gd,Ce and Y elements on texture,recrystallization and mechanical properties of Mg–1.5Zn alloys was investigated.The results show that the addition of Gd,Ce and Y elements in Mg–1.5Zn alloy,which rolled at 450℃ and subsequently annealed at 350℃ for 1h,can effectively weaken and modify the basal texture,characterized by the splitting basal pole toward to transverse direction,leading to the yield and tensile strength,the highest along the rolling direction and the lowest along the transverse direction.Besides,the unique basal texture contributes to the significant improvement of elongation at room temperature.Electron back scattering diffraction(EBSD)analysis indicated that the non-basal texture in Mg–1.5Zn–0.2RE alloys can be attributed to obstructive effect of static recrystallization and the non-basal orientation grains nucleation near pre-existing grain boundaries during annealing.Specially,the Mg–1.5Zn–0.2Gd sheet exhibits much excellent plasticity with the elongation of 27%than Mg–1.5Zn–0.2Ce and Mg–1.5Zn–0.2Y alloys,resulting from the less and smaller second phase of MgZnGd.
基金supported by Strategic Priority Research Program of the Chinese Academy of Sciences (XDB06050100)Natural Key Research and Development Program of China (2016YFC0304201, 2016YFC0304206)Natural Science Foundation of China (No. 51871225)
文摘The heat-affected zone(HAZ) of electron beam welded(EBW) joint normally undergoes a unique heat-treating process consisting of rapid temperature rising and dropping stages, resulting in temperature-gradient in HAZ as a function of the distance to fusion zone(FZ). In the current work,microstructure, elements distribution and crystallographic orientation of three parts(near base material(BM) zone, mid-HAZ and near-FZ) in the HAZ of Ti-6Al-4V alloy were systematically investigated. The microstructure observation revealed that the microstructural variation from near-BM to near-FZ included the reduction of primary α(αp) grains, the increase of transformed β structure(βt) and the formation of various α structures. The rim-α, dendritic α and abnormal secondary α(αs) colonies formed in the mid-HAZ, while the "ghost" structures grew in the near-FZ respectively. The electron probe microanalyzer(EPMA) and electron back-scattered diffraction(EBSD) technologies were employed to evaluate the elements diffusion and texture evolution during the unique thermal process of welding. The formation of the various α structures in the HAZ were discussed based on the EPMA and EBSD results. Finally, the nanoindentation hardness of "ghost" structures was presented and compared with nearby βt regions.
基金National Key R&D Program of China(Grant No.2016YFB0300305)National Natural Science Foundation of China(Grant Nos.51671049 and 51931002)the Postdoctoral Science Foundation of China(Grant No.2018M640257).
文摘High-grade non-oriented silicon steel with higher permeability and lower core loss has become the pursed target with the rapid developnient of electrical machines.The effects of rare-earth(RE)element on recrystallization texture in RE-doped Fe-3.1 wt.%Si-1.2 wt.%Al non-oriented silicon steel were investigated by macro-and micro-texture analyses.Nonlinear variation of recrystallization texture with RE element content was observed.In the competition among main recrystallization texture components,favorable{113}<361>and X fiber(<001>//ND)are strengthened and unfavorable y fiber is evidently decreased by the addition of RE element,whereas the effect of RE element is reversed by excess RE element.The recrystallization texture development is determined by RE-affected nucleation and grain growth in terms of grain boundary migration related to segregation and inclusion.The properly inhibited grain boundary mobility can promote favorable recrystallization texture by the improved nucleation and efficient grain growth.
基金supported by National Natural Science Founda-tion of China(Grant Nos.51971113,51905279,11972202)Zhe-jiang Provincial Natural Science Foundation of China(Grant No.LY21A020002).
文摘In this study,a reduced-order crystal plasticity finite element(CPFE)model was developed to study the effects of the microstructural morphology and crystallographic texture on the mechanical anisotropy of selective laser melted(SLMed)Ti-6Al-4V.First,both hierarchical and equiaxed microstructures in columnar prior grains were modeled to examine the influence of the microstructural morphology on mechanical anisotropy.Second,the effects of crystallographic anisotropy and textural variability on mechanical anisotropy were investigated at the granular and representative volume element(RVE)scales,respectively.The results show that hierarchical and equiaxed CPFE models with the same crystallographic texture exhibit the same mechanical anisotropy.At the granular scale,the significance of crystallographic anisotropy varies with different crystal orientations.This indicates that the present SLMed Ti-6Al-4V sample with weak mechanical anisotropy resulted from the synthetic effect of crystallographic anisotropies at the granular scale.Therefore,combinations of various crystallographic textures were applied to the reduced-order CPFE model to design SLMed Ti-6Al-4V with different mechanical anisotropies.Thus,the crystallographic texture is considered the main controlling variable for the mechanical anisotropy of SLMed Ti-6Al-4V in this study.
基金supports from the National Research Foundation of Korea funded by the Ministry of Education (No. 2018R1A6A1A03024509, NRF-2023R1A2C1005121)
文摘The mechanical properties of an extruded Mg-10Gd sample, specifically designed for vascular stents, are crucial for predicting its behavior under service conditions. Achieving homogeneous stresses in the hoop direction, essential for characterizing vascular stents, poses challenges in experimental testing based on standard specimens featuring a reduced cross section. This study utilizes an elasto-visco-plastic self-consistent polycrystal model(ΔEVPSC) with the predominant twinning reorientation(PTR) scheme as a numerical tool, offering an alternative to mechanical testing. For verification, various mechanical experiments, such as uniaxial tension, compression, notched-bar tension, three-point bending, and C-ring compression tests, were conducted. The resulting force vs. displacement curves and textures were then compared with those based on the ΔEVPSC model. The computational model's significance is highlighted by simulation results demonstrating that the differential hardening along with a weak strength differential effect observed in the Mg-10Gd sample is a result of the interplay between micromechanical deformation mechanisms and deformation-induced texture evolution. Furthermore, the study highlights that incorporating the axisymmetric texture from the as-received material incorporating the measured texture gradient significantly improves predictive accuracy on the strength in the hoop direction. Ultimately, the findings suggest that the ΔEVPSC model can effectively predict the mechanical behavior resulting from loading scenarios that are impossible to realize experimentally, emphasizing its valuable contribution as a digital twin.
