Microstructure, Thermal Conductivity and Mechanical Properties of the Mg–Zn–Sb Ternary Alloys

Abstract

A novel Mg alloys of Mg–xZn–ySb (x = 0, 2, 4, 6; y = 0, 0.2, 0.5, 0.8, 1.2) were designed and their microstructure, thermal conductivity and mechanical properties were systematically investigated in the present study. The as-cast Mg–Zn–Sb ternary alloys consist of α-Mg, Mg4Zn7 and Mg3Sb2 phases. Sb addition can refine the eutectic structure (α-Mg + Mg4Zn7) by the growth of Mg4Zn7 on Mg3Sb2 phases. The thermal conductivity of Mg–Zn–Sb alloys decreased with increasing Sb content. There existed an interactive effect of Zn/Sb on the thermal conductivity of the Mg–Zn–Sb alloys. The negative effect of Sb addition on thermal conductivity of alloys was getting smaller with increasing Zn content in alloys. The negative effect of Mg3Sb2 phases on the thermal conductivity of alloys could be weakened by the formation of weak-scattering Mg4Zn7 coated on Mg3Sb2 phases. The best refinement effect on microstructure could be obtained with 0.8 wt%Sb addition. Mg–4Zn–0.8Sb alloy possess the best comprehensive properties with thermal conductivity of over than 120 W/(m·K) and UTS of 185.6 MPa.