等通道挤压Mg2Si增强ZK60镁合金的显微组织及力学性能

he effects of Equal Channel Angular Pressing(ECAP) on microstructure, mechanical properties at room temperature and high-temperature creep resistance of ZK60+2Si alloy were investigated. Experimental results show that, the components of as-cast alloy are mainly -Mg matrix, Mg2Si and MgZn phases. In the process of ECAP, the original coarse Chinese-script Mg2Si phase are significantly broken into particles which tend to diffuse distribution, and the matrix is also been refined. After 4 passes of EACP, the tensile strength and elongation of alloy at room temperature increases from 154.8MPa, 4.5% to 270MPa, 17.5% respectively. After 6 passes of EACP, elongation further increases to 21%, however, tensile strength drops to 261MPa. The high-temperature creep life of alloy is extended from 20h to 203h, and steady creep rate decrease an order of magnitude. It is mainly because the tiny Mg2Si particles prevent grain boundary sliding effectively.