Microstructure and mechanical properties of as-cast Mg-4Zn-0.5Zr-0.2Cu-0.2Ce alloy

ABSTRACTIn this study, an approach is proposed to improve the microstructure and mechanical properties of Mg-4Zn-0.5Zr alloy by combining trace Cu and rare earth Ce addition. The results showed that Cu and Ce additions led to obvious grain refinement and the formation of Mg-Zn-Cu and Mg-Zn-Ce phases. The Mg-Zn-Ce phase was identified to have an orthorhombic structure. The length of the [0001]α rods in the Cu-containing alloys remarkably decreased. The yield strength increased slightly after Cu and Ce co-addition, which was attributed to grain refinement and precipitation strengthening. The coarse Mg-Zn-Ce phase distributed at the grain boundaries would reduce the ductility by promoting crack propagation during tensile processes.