(中北大學 材料科學與工程學院，太原 030051)
摘 要: 利用高溫拉伸力學性能測試儀、掃描電鏡(SEM)和DTA等測試分析手段，研究不同含量Y對AlSi7Cu2Mg合金的高溫力學性能的影響。結果表明：隨溫度的升高，Y含量為0.15%(質量分數)的AlSi7Cu2Mg合金的強度及伸長率均呈下降趨勢；隨著Y含量的增加，AlSi7Cu2Mg合金在250 ℃的高溫強度(抗拉強度和屈服強度)和伸長率先增加后降低；Y含量為0.1%的AlSi7Cu2Mg合金的高溫力學性能最高，抗拉強度、屈服強度和伸長率分別為275 MPa、240 MPa和12.4%；微量Y對AlSi7Cu2Mg合金的強化作用主要是其對Si相的變質細化作用，在Y含量為0.1%時，Si相獲得最佳的變質效果。
關鍵字: 稀土Y；Al-Si-Cu-Mg 合金；高溫力學性能；變質
（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
