对汽车发动机用AM50合金进行了Er合金化处理；采用扫描电镜（SEM），X射线衍射仪（XRD），浸泡试验和电化学试验研究了Er含量对AM50合金组织和耐蚀性的影响。结果表明：Er微合金化的AM50合金中除了含有α-Mg相和β-Mg₁₇Al₁₂相外，还形成了Al₇ErMn₅相和Al₃Er相；随着Er含量的增加，合金的腐蚀速率总体表现为先降低而后升高的趋势，腐蚀后抗拉强度呈现先增加而后降低的趋势，而强度损失呈现先减小而后增大的趋势； Er添加量为0.5%（质量分数）时，AM50合金具有最佳耐蚀性和拉伸性能。

AM50 alloy for automobile engine was microalloyed by addition of Er. The effects of Er content on microstructure and corrosion resistance of AM50 alloy were studied through scanning electron microscopy (SEM), X-ray diffraction (XRD), immersion test and electrochemical test. The results show that the Er-microalloyed AM50 alloy contained phases of α-Mg, β-Mg₁₇Al₁₂, Al₇ErMn₅ and Al₃Er. With the increase of Er content, the corrosion rate of the alloy first decreased and then increased in general, but the tensile strength increased first and then decreased, and the strength loss displayed the same tendency with the corrosion rate. The AM50 alloy had the best corrosion resistance and tensile properties when the addition of Er was 0.5% (mass).