AZ31镁合金单晶初始屈服行为的数值模拟  

Numerical simulation of initial yield surface of single crystal AZ31

作　　者：蓝永庭[1] 李武军[1] 李启袭[1] 张克实[2] 

机构地区：[1]广西科技大学职业技术教育学院,广西柳州545006 [2]广西大学工程防灾与结构安全教育部重点实验室,广西南宁530004

出　　处：《广西科技大学学报》2015年第3期18-23,共6页Journal of Guangxi University of Science and Technology

基　　金：国家自然科学基金项目(11462002;11272094);广西工学院科学研究基金项目(院科自1074023)资助

摘　　要：为了研究镁合金单晶塑性流动规律,同时考虑滑移与孪生变形机制,在晶体塑性理论基础上建立镁合金晶体本构关系.结合有限元方法,针对AZ31镁合金单晶材料的初始屈服面形状变化开展数值研究,即分别对3种双轴加载下2种平移应变2×10-4和5×10-4的屈服面形状进行预测.由预测结果与试验数据比较分析得出以下结论:预测的2种平移应变的屈服面形状都呈扁长的环形,表现出单晶塑性各向异性性质;本质上,初始屈服面的形状变化是由细观变形机制的启动情况决定的;镁合金单晶应变硬化具有明显的运动硬化特征.For investigation of the plastic flow law of single crystal Mg alloy, the constitutive relation of Mg alloy is established with the crystal plasticity theory based on the mechanism of slip and twinning deformation. The numerical simulation for the initial yield surface of single crystal AZ31 are carried out by using the finite element method （FEM）. That is, the initial yield surfaces are predicted in offset 2×10^-4 and 5×10^-4 under three types of biaxial loading, respectively. By comparing the simulation results with the experimental data, it can be concluded that （1） the initial yield surfaces in offset 2×10^-4 and 5×10^-4 all present the flat ring, which indicates the anisotropic characteristic of crystal plasticity; （2） in essence, the variation of initial yield surfaces depend on the activity of meso deformation mechanism; （3） the strain hardening of single crystal Mg alloy show the obvious characteristic of kinematic hardening.

关 键 词：AZ31单晶 孪生变形 初始屈服面 平移应变 运动硬化 

分 类 号：O34[理学—固体力学] TG14[理学—力学]