AZ91D镁合金碳质法细化工艺及机理研究

Research on Refinement Mechanism of AZ91D Alloy by Carbonaceous Mechanism

研究了不同工艺条件下添加MgCO3对AZ91D镁合金微观组织的影响。结果表明,MgCO3是一种良好的晶粒细化剂。未经细化的AZ91D镁合金的晶粒度为180.4μm,当MgCO3加入量为1wt%、在740℃加入时,细化效果最佳,晶粒度为79.7μm。当镁合金中不含Mn时,添加含碳变质剂后无细化效果,Mn在碳质法中是不可或缺的,该元素是异质形核核心的组成元素。

The effects of microstructure on magnesium alloy under different process were studied.The results show that AZ91D alloy can be effectively refined by MgCO3.The best results can be obtained when adding 1%MgCO3 into the magnesium alloy at 740 ℃,and the average grain size of α-Mg grain decreases from about 180.4 μm to 79.7 μm.And when there is no Mn element in magnesium alloy,no refinement is found after adding MgCO3,it is because that Mn is indispensable to the grain refinement,it is the composition element of nucleant in Mn-containing magnesium alloy.