Microstructure evolution, mechanical properties and diffusion behaviour of Mg-6Zn-2Gd-0.5Zr alloy during homogenization

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2018,（12）
• 页码范围: 2246-2255
• 页数: 10页
• 语种: 英文

摘要

The microstructure evolution and mechanical properties of Mg-6Zn-2Gd-0.5Zr alloy during homogenization treatment were investigated.The as-cast alloy was found to be composed of dendritic primary α-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 α-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.