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采用OM、SEM和XRD研究了添加微量稀土元素Y对ZL205A合金的流动性及T6热处理前后的微观组织和力学性能的影响,并检测了合金的流动性。结果表明,当Y质量分数达到0.2%和0.3%时,合金的晶粒细化效果相对较好,随着Y含量的增加,θ相从沿着晶界的网状分布逐渐向局部团聚,合金的抗拉强度和屈服强度降低;微量Y会使ZL205A合金的流动性降低;Y质量分数为0.3%的ZL205A合金在T6处理后,合金的抗拉强度和延伸率均大幅度提高;热处理能够降低合金中的成分偏析并能够改善材料的组织形态,促使合金具有相对较好的综合力学性能;添加微量Y以后,晶界上的难熔化合物Al Cu Y促使晶粒内部的θ相数量减少,是造成合金力学性能降低的重要原因。
The effects of adding rare earth element Y on the fluidity of ZL205A alloy and the microstructure and mechanical properties before and after T6 heat treatment were investigated by OM, SEM and XRD. The fluidity of the alloy was also tested. The results show that when Y content reaches 0.2% and 0.3%, the grain refinement effect of the alloy is relatively good. As the Y content increases, the θ phase gradually reacts locally with the network distribution along the grain boundaries. The alloy The tensile strength and yield strength of ZL205A alloy decreased with the addition of trace amount of Y. The tensile strength and elongation of ZL205A alloy with 0.3% Y mass fraction increased significantly after T6 treatment and the heat treatment could be reduced The segregation of the components in the alloy can improve the microstructure of the alloy and promote the mechanical properties of the alloy. After the addition of trace amount of Y, the amount of θ phase in the grain decreases due to Al Cu Y in the grain boundary The mechanical properties of the alloy to reduce the important reasons.