Cu,Ce 对Al-7Si-0.35Mg 合金显微组织和力学性能的影响

摘要

The influences of Cu and Ce on the microstructures and mechanical properties of Al-7Si-0. 35Mg alloys were investigated by using the control variables.The alloys underwent the same heat treat-ment:solution at 505 ℃ for ten hours.Then,the specimens were immediately cooled by water quenching. Finally,the samples were aged at 160 ℃ for 6 hours.The results have shown that Cu and Ce have a signif-icant influence on the improvement of the tensile strength and elongation of the heat treated alloys.After heat treatment,the tensile strength of Al-7Si-0.35Mg alloy can be increased by more than 50% with 3.4%~4.0% Cu,when the Ce content is certain.The tensile strengths of Al-7Si-0.35Mg alloys with 3.6% ~3.8% Cu increase above 390 MPa.Ce has an effective modification on the morphology of eutectic silicon. When the Cu content is certain,the elongations of alloys can be improved from 4.2% to 7.4% with 0.15%Ce.Adding excess Cu and Ce to Al-7Si-0.35Mg alloys,Al9 Ce2 Cu5 Si3 phases emerge.The results have il-lustrated that Al-7Si-0.35Mg alloys with 3.6% Cu and 0.15% Ce can attain good comprehensive tensile properties.%采用控制变量法,研究了 Cu,Ce 元素添加对 Al-7 Si-0.35 Mg 合金铸态及505℃10h固溶淬火+160℃6 h时效热处理后显微组织和力学性能的影响.Cu,Ce元素对热处理态合金的强度、塑性影响显著.热处理态下,Ce含量一定时,添加3.4%~4.0%的 Cu 元素能使Al-7Si-0.35 Mg合金的断裂强度提高50%以上.添加3.6%~3.8%的 Cu 元素时,合金的抗拉强度超过了390 MPa；Ce 可以有效改善共晶硅的形态,提高合金的伸长率.当Cu含量一定时,添加0.15%的 Ce,Al-7Si-0.35Mg~3.6Cu 合金的伸长率从4.2%提高到7.4%.添加过量的Cu,Ce元素,合金中会生成针状的Al9 Ce2 Cu5 Si3四元相.实验结果表明, Al-7Si-0.35Mg合金中同时添加3.6% Cu 和0.15% Ce时,材料有良好的综合拉伸性能.