中文摘要：

通过合金制备、组织观察和拉伸实验,研究了Y和Sm对镁合金AZ81组织和力学性能的影响。结果表明,适量的Y和Sm加入镁合金AZ81后可生成高熔点的Al2Y和Al2Sm相,从而细化晶粒,改善组织。在室温和150℃下,合金的抗拉强度和伸长率均随着Y和Sm总含量的增加先升高后降低,其中,Y和Sm总含量为1.8%（质量分数）时,合金的力学性能最好。

英文摘要：

The effect of rare earth elements Y and Sm on the microstructure and mechanical properties of magnesium alloy AZ81 has been investigated by alloy preparation,microstructure observation and tensile tests. The results show that the formation of Al2 Y and Al2 Sm phases with high melting point is observed in magnesium alloy AZ81 after proper addition of Y and Sm. It leads to grain refinement and microstructure improvement of the alloy. With the increase of Y and Sm addition,the tensile strength and elongation of the alloy at room temperature and 150℃ increase at first and then decrease,and reach the peak value at 1. 8wt% Y and Sm.