Microstructure of Mg–In Alloy Systems and Their Room Temperature Rollability

Abstract

The Mg0.1In0.9 phase with FCC structure was formed in Mg–In and Mg–Al–In alloys. The LCR (Limiting Cold-Rolling ratio) at room temperature tended to increase with increasing area fraction of the Mg0.1In0.9 phase, and the LCR achieved 80% for the single Mg0.1In0.9 phase in both alloys. The hardness value of the Mg0.1In0.9 phase in the Mg–In binary alloys increased after rolling originated from grain-refinement by recrystallization and precipitation hardening due to processing heat generated by rolling at room temperature. On the other hand, the Mg0.1In0.9 phase formed in the Mg–Al–In ternary alloys was stable at room temperature and work hardened after rolling. Since the Mg0.1In0.9 phase dissolves about 5 mol% of Al, substituting Al for In in the Mg–In alloy was effective in reducing density. The density of the Mg80Al7In13 (mol%) alloy is 2.60 Mg/m3, which is lower than that of Al, and the LCR showed 49%. In Mg–In alloys, the substitution of Al is effective in developing alloys that are easy to process at room temperature and have low density, because the Mg0.1In0.9 phase has a solid solution of Al and contributes to phase stabilization at room temperature.