Influences of process parameters on microstructure and mechanical properties of AlSi7Mg aluminum alloy components formed by squeeze casting

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. © 2021, Science Press. All right reserved.