AZ31镁合金的热塑性变形行为及组织演化

Thermal Plastic Deformation Behavior and Microstructure Evolution of AZ31 Magnesium Alloy

采用Gleeble-3800热模拟软件对退火后的AZ31镁合金的热塑性变形行为和组织演化进行研究。AZ31镁合金压缩温度为100～400℃,应变速率分别为0.001、0.1、10 s^(-1),压缩变形量为50%。研究了变形温度和应变速率对AZ31镁合金变形行为的影响。分析了镁合金的组织演化和断口形貌。结果表明,AZ31镁合金的最大应力随应变速率的增大而增大,随温度的升高而减小。在较低温度(100℃)和应变速率(0.001 s^(-1))下,组织是不均匀的,由细晶粒和粗晶粒以及一些孪晶组成。将温度提高到200℃,微观组织内大部分晶粒非常细小,动态再结晶发生得更为完全。继续提高温度到300℃以及400℃,晶粒有粗化的趋势。随着应变速率增加到0.1 s^(-1)和10 s^(-1),动态再结晶在300℃完全发生。

The thermal plastic deformation behavior and microstructure evolution of annealed AZ31 magnesium alloy were explored by using Gleeble-3800 thermal simulator.The AZ31 magnesium alloy was compressed at temperature of 100℃to 400℃,strain rate of 0.001 s-1,0.1 s-1,10 s-1and the amount of compression deformation of 50%.The effects of deformation temperature and strain rate on the deformation behavior of AZ31 alloy were studied.The microstructure evolution and fracture morphology of magnesium alloy were analyzed.The results show that the maximum stress of AZ31 magnesium alloy increases with the increase of the strain rate and decreases with the increase of the temperature.At lower temperature(100℃)and strain rate(0.001 s-1),the microstructure is heterogeneous and consists of fine and coarser grain,as well as some twins.To increase the temperature to 200℃,the size of most grains in microstructure is very small,the dynamic recrystallization happens more completely.Continue to increase the temperature to 300℃and 400℃,the grain have a tendency of coarsening.As the strain rate increases to 0.1 s-1and 10 s-1,the dynamic recrystallization finishes at 300℃.