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.

Effect of Sb on the grain refinement and tensile properties of Mg-10Zn-5Al alloys

In the present research, the Sb-alloying method was adopted, and the grain re finement and tensile properties of as-cast Mg-10Zn-5Al alloys with varying Sb addition were investigated.The results showed that with the Sb addition, a new phase (Mg3Sb2) of high melting point forms in the alloy beside the α-Mg matrix, τ-Mg32(Al, Zn)49 phase and φ-Al2Mg5Zn2 phase.With an appropriate amount of Sb addition, the morphologies of the secondary phases and the matrix are changed and the grains are refined.When Sb addition is 0.6wt.%, both ambient and high temperature tensile strengths of the alloy reach their maximum.The hardness of the alloy increases with the increasing of Sb addition.With proper addition of Sb, the tensile failure mode of the alloy changes from cleavage fracture to quasi-cleavage fracture, showing good enhancement effect.