The microstructure evolution and mechanical properties of Mg-6 Zn-2 Gd-0.5 Zr alloy during homogenization treatment were investigated. The as-cast alloy was found to be composed of dendritic primaryα-Mg matrix, α-Mg +W（Mg3Zn3Gd2） eutectic along grain boundaries, and icosahedral quasicrystalline I（Mg3Zn6Gd） phase within α-Mg matrix. During homogenization process, α-Mg +W（Mg3Zn3Gd2） eutectic and I phase gradually dissolved into a-Mg matrix, while some rod-like rare earth hydrides（GdH2）formed within α-Mg matrix. Both the tensile yield strength and the elongation showed a similar tendency as a function of homogenization temperature and holding time. The optimized homogenization parameter was determined to be 505℃ for 16 h according to the microstructure evolution. Furthermore,the diffusion kinetics equation of the solute elements derived from the Gauss model was established to predict the segregation ratio of Gd element as a function of holding time, which was proved to be effective to evaluate the homogenization effect of the experimental alloy.
