均匀化退火对ZM21镁合金组织的影响

Effect of homogenizing annealing on microstructure of ZM21 magnesium alloy

采用光学显微镜、扫描电镜、能谱分析等方法,研究了均匀化退火对ZM21镁合金组织的影响。结果表明:ZM21合金铸态组织中存在偏析,Zn等溶质元素富集到晶界处;ZM21镁合金中的化合物随着退火温度的提高而减少,693K保温10 h为ZM21较优的均匀化退火工艺;均匀化处理后,ZM21镁合金中含有MgZn相、MnZn3相和Mn单质相,其中Mn单质相是由过饱和α-Mg固溶体析出的,MnZn3相是由Zn和Mn原子通过高温长时间扩散结合生成的。

The effect of homogenization annealing on the microstructure of ZM21 magnesium alloy is investigated by means of optical microscope,SEM and EDS.The results indicate that there is segregation in the as-cast ZM21 alloy,and the solute elements such as Zn are concentrated at the grain boundary;the compounds in ZM21 magnesium alloy are decreased with the increase of annealing temperature,the better homogenization annealing process for ZM21 is at 693K for 10h.After the homogenization treatment,there are MgZn phase,MnZn3 phase and Mn single phase in ZM21 magnesium alloy,in which Mn single phase is precipitated from supersaturatedα-Mg solid solution,MnZn3 phase is formed by the combination of Zn and Mn atoms through diffusion at a high temperature for long time.