通过含量的变化研究了微量稀土元素Er对A356.2合金微观组织和力学性能的影响规律。实验结果表明,添加微量的Er元素不仅可通过在合金熔体中产生大量异质形核核心(Al_3Er)细化初生α-Al晶粒,而且Er元素还可有效细化铝-硅共晶团,从而显著提高合金的力学性能。当Er含量为1%时合金的力学性能最高,抗拉强度为240 MPa,伸长率为9.8%。 The influence of rare earth element Er on the microstructure and mechanical properties of A356.2 alloy was studied by the change of content. The experimental results show that addition of a trace amount of Er element can not only refine the primary α-Al grains by producing a large amount of heterogeneous nucleation nuclei (Al_3Er) in the alloy melt, but also effectively refine the aluminum-silicon eutectic , Thus significantly improve the mechanical properties of the alloy. When Er content is 1%, the mechanical properties of the alloy are the highest, the tensile strength is 240 MPa and the elongation is 9.8%.