Effect of homogenization treatment on microstructure evolution and the distributions of RE and Zr elements in various Mg–Li–RE–Zr alloys

Mg–3Li–0.4Zr alloys containing RE elements (Gd, La, Nd) (Mg–3Li–RE–0.4Zr alloys) are investigated to reveal the influence of homogenization treatment on microstructures and distributions of RE, Zr elements. It is found that 300 °C × 24 h homogenization treatment shows better improvement on the microstructure including the refinement of grain size, the dispersion of cellular dendrite and low melting point particles. Before treatment, La and Nd segregate effectively at grain boundary and Zr segregates in the form of precipitates. Homogenization treatment induces the reduction of RE segregation. However, the segregation of Zr in precipitates cannot be abated due to the relatively low diffusion rate compared with RE elements.