Microstructure and mechanical properties of as-cast and solution-treated Mg-Zn-Gd-based alloys reinforced with quasicrystals

Abstract

Abstract The microstructure and mechanical properties of as-cast and solution-treated Mg-xZn-yGd (x/y = 6, at.%) alloys reinforced with quasicrystals have been investigated. The results indicate that with the increase in the alloying elements contents, the dendritic microstructure is refined, the corresponding strength gradually increased, and the elongation gradually decreased as the increase in the second phase sizes leads to stress concentration under as-cast and solution-treated conditions. For as-cast alloys, micro-cracks originated in the α-Mg matrix and quasicrystals interface. The fracture mode exhibits intergranular fracture characteristics. After solution treatment, the yield strength decreased, and the ultimate tensile strength and elongation increased clearly due to the Mg2Zn3 phase dissolution and the second phase sizes decreasing. The fracture mode changes to transgranular fracture.