稀土Er对ZL114A合金微观组织和性能的影响

Effect of Rare Earth Er on the Microstructure and Properties of the ZL114A Alloy

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 rare earth element Er.SEM,XRD,DSC and other material analysis methods were used to study the effects of different Er contents on the microstructure and mechanical properties of the ZL114A aluminium alloy.The results show that grain refinement can be achieved by adding suitable Er,the coarse dendrite structure in the alloy gradually tends to be spheroidized,the crystallization temperature of the primaryα-Al phase and eutectic Si decreases,and the precipitated phase Al3Er is enriched on eutectic Si,which plays a role in heterogeneous nucleation.With increasing Er content,eutectic Si evolves 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 properties decrease.The alloy exhibits optimal performance when 0.5 wt.%Er is added,with the tensile strength and elongation rate increasing by 11.43%and 52.8%,respectively.