AZ91D镁合金高温压缩过程中的微观组织演变

Microstructure evolution of AZ91D magnesium alloy during high temperature compression

采用Gleeble-1500热模拟实验机对AZ91D镁合金在400℃、0.01 s-1的条件下进行不同压缩真应变量(1%、10%、60%、100%)的高温压缩实验,利用光学显微镜、透射电镜观察压缩变形过程中合金的显微组织演变。结果表明:在压缩变形的初始阶段,{101 2}孪生是主要的变形机制,孪晶的尺寸较大;在随后的变形过程中孪晶发生破碎,尺寸变小;随着变形的进一步进行,孪晶之间相互交叉,在孪晶界及孪晶交叉畸变较大的区域成为再结晶的形核区。

High temperature compression tests of AZ91D magnesium alloy were performed on Gleeble-1500 thermal mechanical simulator at strain rate of 0.01 s^-1 and temperature of 400 ℃. The microstructure evolution of the alloy during compression was examined by optical microscope （OM） and transmission electron microscope （TEM）, The results show that {101^-2} twin is primary deformation mechanism and the size of twins is larger at the initial stage of compressive deformation, however, these larger twins will be fragmented and become small under large deformation. With the increasing of strain, some twins cross each other and dynamic recrystallization （DRX） grains are nucleated at twin boundaries and twin intersections.