摘要
将AZ31B镁合金铸锭加工成合适尺寸的板坯开展常规冷轧实验。利用电子背散射(Electron Back-Scattered Diffraction,EBSD)技术对轧制后板材的微观组织进行表征,并借助粘塑性自洽(Visco-Plasitic Self-Consistant,VPSC)模型模拟板材的拉伸变形行为。研究轧下量对轧制后板材在室温下力学性能的影响机理,进一步明晰轧下量-变形机制-力学性能之间的联系,进而为优化室温下镁合金板材的力学性能奠定理论基础。结果表明:冷轧过程中,大量{10-12}拉伸孪生被激活,少量{10-11}~{10-12}二次孪生被激活。随着冷轧轧下量增加,晶粒c轴趋向于平行板材法向(Normal Direction,ND),导致{10-12}拉伸孪晶体积分数逐渐降低。此外,大轧下量板材内滑移系被激活的比例更大,对滑移和孪生在拉伸过程中被激活的阻碍作用更强,滑移和孪生的临界剪切应力(Critical Resolved Shear Stress,CRSS)显著升高,进而提高板材的屈服强度;但是,由于{0001}基面滑移和{10-12}拉伸孪生被激活的比例降低,限制了{0001}基面滑移协调塑性变形的贡献,板材的伸长率明显下降。
Conventional cold rolling experiments were conducted on plate blanks processed from as-cast AZ31B magnesium alloy.The microstructure of the rolled sheets was characterized by the Electron Back-Scattered Diffraction(EBSD)technique,and the Visco-Plasitic Self-Consistant(VPSC)model was used to simulate the tensile deformation behavior of the sheets.The mechanism of the cold rolling reduction on the mechanical properties of the rolled sheets was investigated at room temperature,aiming to elucidate the relationship among cold rolling reduction,deformation mechanism,and mechanical properties,thereby establishing a theoretical foundation for optimizing the mechanical properties of magnesium alloy sheets at room temperature.The results showed that a large number of{10-12}extension twins were activated during cold rolling,along with a small number of{10-11}-{10-12}secondary twinning.With the increase of cold rolling reduction,the c-axis of grains tended to align parallel to the Normal Direction(ND)of the sheets,resulting in a gradual decrease in the volume fraction of{10-12}extension twins.In addition,sheets with higher reduction exhibited a greater activation proportion of slip systems,which enhanced the resistance to the activation of slip and twinning during tensile testing,and the Critical Resolved Shear Stress(CRSS)of slip and twinning was significantly elevated,thereby improving the yield strength of the sheets.However,the reduced activation of{0001}basal slip and{10-12}extension twinning limited their contribution to coordinating plastic deformation during tensile loading,so the elongation of the sheets decreased significantly.
作者
金文瀚
段国升
王硕
JIN Wenhan;DUAN Guosheng;WANG Shuo(College of Aerospace Engineering,Shenyang Aerospace University,Shenyang 110136,China;Shenyang Xinghua Aviation Electrical Appliance Co,Ltd.,Shenyang 100144,China)
出处
《郑州航空工业管理学院学报》
2025年第2期85-91,共7页
Journal of Zhengzhou University of Aeronautics
基金
国家自然科学基金青年科学基金项目(51901140)。
关键词
冷轧
EBSD
变形机制
VPSC
力学性能
cold rolling
EBSD
deformation mechanism
VPSC
mechanical property
