Effect of Ce addition on the microstructure and tensile properties of extruded Mg-Zn-Zr alloys

The microstructure and tensile properties of extruded Mg-Zn-Zr-Ce alloys with different Ce contents were investigated. Ce addition to ternary Mg-Zn-Zr alloy resulted in significant grain refinement as well as a change in the type of second phase particles from MgZn to Ce(Mg1−xZnx)11, which has a C-centered orthorhombic structure with lattice parameters of a=0.999 nm, b=1.146 nm, and c=0.976 nm. However, fine MgZn2 precipitates were found to exist in the extruded alloys regardless of the level of Ce content. The yield and ultimate strengths of the extruded alloys were significantly increased by Ce addition although the presence of coarse Ce(Mg1−xZnx)11 particles has an adverse effect on ductility.