通过向过共晶铝硅合金中加入稀土元素Er来球化、粒化初生硅和共晶硅,研究了不同Er含量对过共晶Al-20%Si合金微观组织及性能的影响。结果表明,向过共晶Al-20%Si合金中添加稀土Er可使得合金中的花瓣状、大块状初生硅钝化、球化;针片状共晶硅细化成珊瑚状、蠕虫状。其中当Er的含量为1%时,微观组织细化效果最明显,初生硅尺寸最小,抗拉强度和伸长率最高。 The effects of Er content on the microstructure and properties of hypereutectic Al-20% Si alloy were studied by spheroidizing and granulating primary silicon and eutectic silicon by adding rare-earth element Er to the hypereutectic Al-Si alloy. The results show that the addition of rare earth Er to the hypereutectic Al-20% Si alloy can deactivate and spheroidize the petal-like and chunk-shaped primary silicon in the alloy. The lamellar eutectic silicon is refined into corals and worms. Among them, when the content of Er is 1%, the microstructure refinement effect is most obvious, the size of primary silicon is the smallest, and the tensile strength and elongation are the highest.