以铸造 ZL114A 铝合金为研究对象，通过加入稀土元素 Er 来改善合金的微观组织，提高其力学性能。 借助SEM、XRD、DSC 等材料分析手段，研究了不同 Er 含量对 ZL114A 铝合金微观组织与力学性能的影响。 结果表明，添加合适的 Er 元素可以达到细化晶粒的目的，合金中粗大的枝晶组织逐渐趋于球化，初生 α-Al 相和共晶 Si 结晶温度下降，析出相 Al3Er 富集在共晶 Si 上，起到异质形核的作用。 随着 Er 含量的增加，共晶 Si 由板条状演化为棒状或近球状，合金的力学性能也随之提高。当 Er 含量超过某一临界值(0.5%，质量分数)，则细化效果不明显，力学性能也有所降低。添加0.5%Er 时，合金的性能最佳，抗拉强度和延伸率分别提高了 11.43%和 52.8%。

The microstructure of a ZL114A alloy and its mechanical properties were improved by the addition of the rareearth element Er. SEM, XRD, DSC and other material analysis methods were used to study the effects of different Ercontents on the microstructure and mechanical properties of the ZL114A aluminium alloy. The results show that grainrefinement can be achieved by adding suitable Er, the coarse dendrite structure in the alloy gradually tends to bespheroidized, the crystallization temperature of the primary α-Al phase and eutectic Si decreases, and the precipitated phaseAl3Er is enriched on eutectic Si, which plays a role in heterogeneous nucleation. With increasing Er content, eutectic Sievolves from slats to rods or near-spherical particles, and the mechanical properties of the alloy also improve. However,when the Er content exceeds a critical value (0.5 wt.%), the refining effect is not significant, and the mechanical propertiesdecrease. The alloy exhibits optimal performance when 0.5 wt.% Er is added, with the tensile strength and elongation rateincreasing by 11.43% and 52.8%, respectively.