AZ31镁合金热压缩过程中晶粒取向和织构的演变

Grain orientation and texture evolution of AZ31 magnesium alloy during hot compression

利用电子背散射衍射(EBSD)取向成像技术分析AZ31铸态镁合金在不同温度和真应变下热压缩的晶粒取向和织构特点,从晶粒取向和织构角度分析不同温度下其动态再结晶(DRX)的类型。结果表明:在热压缩过程中,350℃时,AZ31铸态镁合金表现为连续动态再结晶(CDRX)特征,新晶粒取向与基体相似,具有较强的{0002}基面织构,以基面滑移为主;500℃时,为旋转动态再结晶(RDRX)特征,真应变为0.5时,新晶粒取向与基体偏转成一定角度,具有两种主要的基面织构,由于动态再结晶的定向形核、择优核心长大和旋转动态再结晶造成这两种基面织构弱于350℃时的{0002}基面织构;且随着真应变的增加,其中一种织构由于滑移系的改变而逐渐消失。

The characteristics for grain orientation and texture of AZ31 magnesium alloy were investigated by the electron back scattering diffraction （EBSD） technique at different temperatures and strains during hot compression. The types of dynamic recrystallization （DRX） for AZ31 magnesium alloy under different temperatures were researched based on the grain orientation and texture. The results show that, at 350 ℃, it displays the characteristics of continue dynamic recrystallization （CDRX）. The new grains are similarly orientated to the basal grain, which has strong {0002} basal texture and is mainly on the basal slip. At 500 ℃, it shows the characteristics of rotation dynamic recrystallizaion （RDRX）. At a true strain of 0.5, the orientation of new grain deviates from the orientation of basal grain. The oriented nucleation, preferred core growth and RDRX attribute to the two different main basal textures, which is weaker than that of {0002} basal texture at 350 ℃. With the true stain increasing, one of the basal textures gradually disappears for altering slip systems.