Mg-12Gd-2Y-1.5Sm-0.5Zr合金中镁稀土相形成机理

Formation of Mg-RE Phases in Mg-12Gd-2Y-Sm-0.5Zr Alloy

通过SF6+CO2气体保护,在大气环境下制备了Mg-12Gd-2Y-1.5Sm-0.5Zr镁合金,并基于电负性理论分析以及应用Miedema生成热模型对合金镁稀土相的形成进行了分析研究。结果表明,铸态合金内除存在α-Mg基体相外,还有Mg5Gd、Mg24Y5和Mg3Sm相;Mg与稀土元素Gd、Y、Sm具有较好的亲和力,镁稀土相的形成有其必然性。

Mg-12Gd-2Y-1.5Sm-0.5Zr alloys were prepared under flux protection.Based on the electronegative theory analysis,Miedema theory（formation heat theory） was employed to explain the formation of Mg-rare earth phase（Mg-RE phase）.The results show that the as-cast alloy consists of α-Mg matrix,Mg5Gd phase,Mg24Y5 phase and Mg3Sm phase.The affinity between Mg and Gd,Y,Sm is better,and it is believed that the Mg-RE phases are presented in Mg-12Gd-2Y-1.5Sm-0.5Zr alloy.