通过金相(OM)和扫描电镜(SEM)的显微组织分析、荧光成分分析(XRF),能谱微区成分分析(EDS)、X射线物相分析(XRD),显微硬度(HV)和差热分析(DSC)等测试手段和方法,对铸态Mg-5Sn-xEr(x=0,0.5,1,1.5,2,2.5,4,6)合金的组织性能进行了全面研究。研究结果表明,稀土Er对Mg-5Sn合金的影响是多方面的,首先是稀土Er对晶粒有明显的细化作用;再就是稀土Er能抑制盘状Mg2Sn第二相的形成,同时促进不规则ErMgSn稀土相的形成,最后就是提高了合金的相转变温度和显微硬度。因此稀土Er对铸态Mg-5Sn合金具有显著的变质效果。 The microstructure analysis, fluorescence composition analysis (XRF), EDS, XRD and microhardness (HV) of metallographic (OM) and scanning electron microscopy (SEM) And Differential Thermal Analysis (DSC) were used to investigate the microstructure and properties of as-cast Mg-5Sn-xEr (x = 0,0.5,1,1.5,2,2.5,4,6) alloys. The results show that the effect of rare earth Er on Mg-5Sn alloy is multifaceted. The first is that rare earth Er has obvious thinning effect on the grain. Then the rare earth Er can restrain the formation of the second phase of discoid Mg2Sn, The rule ErMgSn rare earth phase formation, the last is to improve the alloy phase transition temperature and microhardness. Therefore, rare earth Er on the as-cast Mg-5Sn alloy has a significant deterioration effect.