Microstructure evolution, mechanical properties and diffusion behaviour of Mg-6Zn-2Gd-0.5Zr alloy during homogenization. Issue 12 (December 2018)

• Record Type: Journal Article
• Authors: Xiao, Lei; Yang, Guangyu; Liu, Yang; Luo, Shifeng; Jie, Wanqi
• Is Part Of: Journal of materials science & technology. Volume 34:Issue 12(2018)
• Page Start: 2246
• Page End: 2255
• Publication Date: 2018-12
• Subjects: Mg alloy -- Homogenization -- Segregation -- Diffusion kinetics; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2018.05.003
• Languages: English
• ISSNs: 1005-0302

Abstract

Abstract: 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 (Mg3 Zn3 Gd2 ) eutectic along grain boundaries, and icosahedral quasicrystalline I (Mg3 Zn6 Gd) phase within α-Mg matrix. During homogenization process, α-Mg + W (Mg3 Zn3 Gd2 ) 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 °C 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.