AZ31镁合金在以孪生主导的塑性变形中力学行为的模拟（英文）

Simulation of mechanical behavior of AZ31 magnesium alloy during twin-dominated large plastic deformation

从实验和黏塑性自洽(VPSC)模拟两个方面定量分析具有织构的AZ31镁合金中孪晶数量及其与应力-应变曲线的关系。沿着两个不同的方向进行压缩以启动{1012}拉伸或者{1011}压缩孪生。{1012}拉伸孪晶在塑性变形的初始阶段形核并且长大到完全吞并母体。当沿着法向压缩时,{1011}孪生和{1011}-{1012}二次孪生在应变量为0.05时开始启动,并且这些孪晶的数量一直增加直到材料断裂,即应变量大于0.15。当沿着横向压缩应变量为0.06时,也会启动{1011}孪生和{1011}-{1012}二次孪生,然后在已经完全发生{1012}孪生的晶粒中大量启动。应用适当的参数,VPSC模型可以准确地判断拉伸孪晶、压缩孪晶和二次孪晶的启动和流动应力以及变形织构。从模拟中可以看出,孪生和滑移具有相同的硬化参数。

Experiments and visco-plastic self-consistent (VPSC) simulations were used to quantify the amount of twinning and the relationship to stress?strain behavior in a textured Mg?3Al?1Zn plate. Two different compression directions were utilized to favor{1012} extension or{1011} compression twinning.{1012} twins nucleate at the beginning of plastic deformation and grow to consume the parent grains completely. During compression along the normal direction,{1011} twinning and{1011}?{1012} double twinning start at strain of 0.05, and the number of twins increases until rupture, above strain of 0.15.{1011} and{1011}?{1012} twinning also occur during compression along the transverse direction, start at strain of 0.06 and then multiply in grains totally reoriented by{1012} twins. Using suitable parameters, the VPSC model can accurately predict the occurrence of extension, compression and double-twinning as well as the flow stresses and deformed textures. According to VPSC simulations, twinning and slip have the same latent hardening parameters.