(中北大学 材料科学与工程学院，太原 030051)
摘 要: 利用高温拉伸力学性能测试仪、扫描电镜(SEM)和DTA等测试分析手段，研究不同含量Y对AlSi7Cu2Mg合金的高温力学性能的影响。结果表明：随温度的升高，Y含量为0.15%(质量分数)的AlSi7Cu2Mg合金的强度及伸长率均呈下降趋势；随着Y含量的增加，AlSi7Cu2Mg合金在250 ℃的高温强度(抗拉强度和屈服强度)和伸长率先增加后降低；Y含量为0.1%的AlSi7Cu2Mg合金的高温力学性能最高，抗拉强度、屈服强度和伸长率分别为275 MPa、240 MPa和12.4%；微量Y对AlSi7Cu2Mg合金的强化作用主要是其对Si相的变质细化作用，在Y含量为0.1%时，Si相获得最佳的变质效果。
关键字: 稀土Y；Al-Si-Cu-Mg 合金；高温力学性能；变质
（School of Materials Science and Engineering, North University of China, Taiyuan 030051, China）
Abstract:The effect of Y contents on the high temperature mechanical properties of AlSi7Cu2Mg alloys was investigated by electronic universal material testing machine, scanning electron microscopy (SEM) and differential thermal analysis (DTA). The results indicate that the ultimate tensile strength and elongation of the AlSi7Cu2Mg alloy with 0.15% Y (mass fraction) decrease with increasing temperature. The ultimate tensile strength, yield strength and elongation of the AlSi7Cu2Mg alloys with 0.1% Y increase up to the maximum value and then decrease with increasing Y content at 250 ℃. The alloy with 0.1% Y has the highest high temperature mechanical properties (ultimate tensile strength of 275 MPa, yield strength of 240 MPa and elongation of 12.4%). The strengthening effect of trace Y on the AlSi7Cu2Mg alloys is mainly relying on the modification of eutectic Si phase, the optimal modification of Si phase can be obtained with 0.1% Y.
Key words: rare earth Y; Al-Si-Cu-Mg alloy; high temperature mechanical properties; modification
