Effects of Sb content on microstructure and mechanical properties of Mg-6Zn-Y-Zr-xSb alloy

Effects of Sb content on microstructure and mechanical properties of Mg-6Zn-Y-Zr-xSb alloy were investigated by OM, SEM, XRD and mechanical property test. The results indicate that addition of Sb can break continuous network structure into particles in the interdendritic spaces, and with increasing Sb content, the volume fraction of these particles increases. The as-cast microstructure of the alloy with low content of Sb consists of α-Mg, Zn-rich phase, eutectic structure (α-Mg+I-phase) and YSb. With increasing Sb content, Mg3Sb2 and Mg4Zn7 phases appear, while I-phase disappears finally. The ultimate tensile strength and elongation increase first with the increase of Sb content, while the mechanical properties reduce at excessive Sb content.