(1. 哈尔滨工业大学 材料科学与工程学院，哈尔滨 150001；
2. 哈尔滨工业大学 机电工程学院，哈尔滨 150001)
摘 要: 借助重力铸造和挤压铸造技术分别成形了AlSi7Mg铝合金模拟构件，利用拉伸试验机、金相显微镜和扫描电镜等手段研究了工艺参数对成形件组织与性能的影响规律。结果表明：与重力铸件相比，挤压铸造件的抗拉强度、伸长率和屈服强度分别提高了41%、562%和0.5%，挤压铸造件的平均晶粒尺寸随着浇注温度、模具温度和保压时间的增加呈现出先减小后增大的趋势。最佳挤压铸造工艺参数范围为浇注温度700~720 ℃、模具温度200~250 ℃、保压15~30 s，在该工艺条件下最好的综合力学性能为抗拉强度221 MPa、屈服强度121.5 MPa和伸长率7.6%。Si、Fe、Mn、Mg等元素在晶界处发生偏析，对挤压铸造成形件的力学性能会产生不利影响。
关键字: AlSi7Mg铝合金；挤压铸造; 微观组织; 力学性能
（1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:AlSi7Mg aluminum alloy components were formed by gravity casting and squeeze casting. Influences of process parameters on microstructure and mechanical properties of formed parts were investigated by tensile test, optical microscopy and scanning electron microscopy. The results show that the yield strength, ultimate tensile strength and elongation of parts formed by squeeze casting increase by 41%, 562% and 0.5%, respectively, comparing with those of parts formed by gravity casting. The average grain size of parts formed by squeeze casting decreases and then increases with increases of pouring temperature, die temperature and dwell time. The optimal process parameters obtained in this research involve the pouring temperature range from 700 ℃ to 720 ℃, die temperature range from 200 ℃ to 250 ℃ and dwell times from 15 s to 30 s. The optimal mechanical properties such as yield strength of 121.5 MPa, ultimate tensile strength of 221 MPa and elongation of 7.6% are achieved under the optimal conditions. The alloy elements such as Si, Fe, Mn and Mg segregate on the grain boundary, which is detrimental to the mechanical properties of parts formed by squeeze casting.
Key words: AlSi7Mg aluminum alloy; squeeze casting; microstructure; mechanical properties
