Effect of Sb on microstructure and mechanical properties in Mg-10Zn-5Al high zinc magnesium alloys

In view of high strength and poor impact toughness of the high-zinc magnesium alloys, the method of micro-alloying was adopted to improve the impact-toughness of Mg-10Zn-5Al high zinc magnesium alloys by adjusting the addition of Sb. The results show that: the dystectic Mg3Sb2 particles formed by Sb and Mg are distributed in the front of dendrite, restrain the growth of the secondary phase and then change the morphology of the secondary phases, which refines the matrix in some extent and improves the impact-toughness of the alloy significantly. But with further increase of Sb addition, Mg3Sb2 particles congregate and form needle-like Mg3Sb2 phase, which dissevers the matrix and leads to the reduction of the strength and impact-toughness of the alloys. Hence, the mechanical prosperities of ZA105 high zinc magnesium alloy are significantly improved with appropriate Sb addition, which provides a new way to extend the application fields of high zinc magnesium alloy.