Deformation-induced microstructures of high-Mn austenite steel was investigated by metallography,X-ray diffraction and SEM.The ε-martensite and slip-bands are deformation-in- duced on the{111} planes,and appear as th...Deformation-induced microstructures of high-Mn austenite steel was investigated by metallography,X-ray diffraction and SEM.The ε-martensite and slip-bands are deformation-in- duced on the{111} planes,and appear as thin straight laths with 60～80° alignment difference be- tween them.It was found that ε-martensite and slip bands are kinked at fcc twin boundaries with the kinked angle 35～40°.The bands of equilateral triangle in the microstructure of tensile deformation are presented.展开更多
借助金相显微镜和SEM观察,研究了Al-(2.86～9.41)Mg合金热轧板及其完全退火后板材的显微组织。结果表明:Al-(2.86～9.41)Mg合金热轧板的晶粒均沿轧向呈纤维状分布,当w(Mg)>6.44%,热轧板中出现明显的滑移网;w(Mg)从6.44%增大至9.41%,...借助金相显微镜和SEM观察,研究了Al-(2.86～9.41)Mg合金热轧板及其完全退火后板材的显微组织。结果表明:Al-(2.86～9.41)Mg合金热轧板的晶粒均沿轧向呈纤维状分布,当w(Mg)>6.44%,热轧板中出现明显的滑移网;w(Mg)从6.44%增大至9.41%,热轧板中滑移带变粗、滑移带网变密集,滑移网波及的范围变广。热轧板经450℃退火处理后均完全再结晶,晶粒形状趋于等轴状。w(Mg)从2.86%增加至9.41%对再结晶晶粒尺寸无明显影响。热轧板经450℃退火处理后,板材基体中存在大量沿轧制方向呈流线分布的AlFeSi相和沿晶界分布的β相,镁含量增加,Al Fe Si尺寸、数量和分布变化不大,但β相的数量明显增多、尺寸明显增大。展开更多
The compressive yielding phenomenon of titanium alloys is not as focused and sufficiently ascertain as the tensile yielding phenomenon.In the present work,the peculiar compressive yielding behavior and the different d...The compressive yielding phenomenon of titanium alloys is not as focused and sufficiently ascertain as the tensile yielding phenomenon.In the present work,the peculiar compressive yielding behavior and the different dynamic responses of three different initial microstructures(singleβ,clavateβand lamellarβ)were investigated in an attractive metastableβtitanium alloy Ti-5553 using electron microscopes/crystallographic calculation/crystal plastic finite element simulation.Results reveal that the distinct compressive yielding behavior,steep peaks of sudden drop in the initial stage(very small true strain 0.03)of stress loading have appeared in the compression stress-strain curves except for the lamellarβinitial microstructure.Dislocation slip is the essential mechanism of the initial yielding behavior.Interlaced multiple-slip bands formed in the singleβinitial microstructure during the warm deformation process.A small quantity of single slip bands was observed in the deformed clavateβinitial microstructure.The abundant varied nano/ultrafineβsprecipitates were nucleated dynamically and dispersedly in all the three deformed initial microstructures.The multiple-slip bands formation and substantial nanoscaleβsresult in the highest peak of flow stress for singleβinitial microstructure.The compressive slip bands are formed early in the elastic–plastic deformation stage.As the increasing strain,the sample showed a significant compressive bulge,or eventually forming a strong adiabatic shear band or crack.These results are expected to provide a reference for the study of deformation behavior and mechanical properties of metastableβtitanium alloys.展开更多
The microstructure and the strain fatigue dislocation substructure of 7075-RRA (Retrogression and Reaging) aluminum alloy have been studied by using transmission electron microscopy. From these, a competitive mechanis...The microstructure and the strain fatigue dislocation substructure of 7075-RRA (Retrogression and Reaging) aluminum alloy have been studied by using transmission electron microscopy. From these, a competitive mechanism of cyclic microscopic softening/hardening is put forward to explain the relation between macroscopic cyclic stability behavior and microscopic substructure.展开更多
文摘Deformation-induced microstructures of high-Mn austenite steel was investigated by metallography,X-ray diffraction and SEM.The ε-martensite and slip-bands are deformation-in- duced on the{111} planes,and appear as thin straight laths with 60～80° alignment difference be- tween them.It was found that ε-martensite and slip bands are kinked at fcc twin boundaries with the kinked angle 35～40°.The bands of equilateral triangle in the microstructure of tensile deformation are presented.
文摘借助金相显微镜和SEM观察,研究了Al-(2.86～9.41)Mg合金热轧板及其完全退火后板材的显微组织。结果表明:Al-(2.86～9.41)Mg合金热轧板的晶粒均沿轧向呈纤维状分布,当w(Mg)>6.44%,热轧板中出现明显的滑移网;w(Mg)从6.44%增大至9.41%,热轧板中滑移带变粗、滑移带网变密集,滑移网波及的范围变广。热轧板经450℃退火处理后均完全再结晶,晶粒形状趋于等轴状。w(Mg)从2.86%增加至9.41%对再结晶晶粒尺寸无明显影响。热轧板经450℃退火处理后,板材基体中存在大量沿轧制方向呈流线分布的AlFeSi相和沿晶界分布的β相,镁含量增加,Al Fe Si尺寸、数量和分布变化不大,但β相的数量明显增多、尺寸明显增大。
基金supported by National Natural Science Foundation of China(51801156)Major State Research Development Program of China(2016YFB0701305)+1 种基金Natural Science Basic Research Plan in Shaanxi Province of China(2018JQ5035)the Fundamental Research Funds for the Central Universities(G2017KY0310).
文摘The compressive yielding phenomenon of titanium alloys is not as focused and sufficiently ascertain as the tensile yielding phenomenon.In the present work,the peculiar compressive yielding behavior and the different dynamic responses of three different initial microstructures(singleβ,clavateβand lamellarβ)were investigated in an attractive metastableβtitanium alloy Ti-5553 using electron microscopes/crystallographic calculation/crystal plastic finite element simulation.Results reveal that the distinct compressive yielding behavior,steep peaks of sudden drop in the initial stage(very small true strain 0.03)of stress loading have appeared in the compression stress-strain curves except for the lamellarβinitial microstructure.Dislocation slip is the essential mechanism of the initial yielding behavior.Interlaced multiple-slip bands formed in the singleβinitial microstructure during the warm deformation process.A small quantity of single slip bands was observed in the deformed clavateβinitial microstructure.The abundant varied nano/ultrafineβsprecipitates were nucleated dynamically and dispersedly in all the three deformed initial microstructures.The multiple-slip bands formation and substantial nanoscaleβsresult in the highest peak of flow stress for singleβinitial microstructure.The compressive slip bands are formed early in the elastic–plastic deformation stage.As the increasing strain,the sample showed a significant compressive bulge,or eventually forming a strong adiabatic shear band or crack.These results are expected to provide a reference for the study of deformation behavior and mechanical properties of metastableβtitanium alloys.
文摘The microstructure and the strain fatigue dislocation substructure of 7075-RRA (Retrogression and Reaging) aluminum alloy have been studied by using transmission electron microscopy. From these, a competitive mechanism of cyclic microscopic softening/hardening is put forward to explain the relation between macroscopic cyclic stability behavior and microscopic substructure.
