Effect of Gd content on high temperature mechanical properties of Mg–Gd–Y–Zr alloy

Abstract

In this study, the compositional dependence of the age hardening response and high temperature tensile properties of the Mg–xGd–3Y–0.5Zr (x=3, 6, 10, and 12wt%) alloys are investigated. The amount of cuboid-shaped phases and β′ precipitates increased significantly with increasing the Gd content. The Mg–10Gd–3Y–0.5Zr alloy exhibited the maximum ultimate tensile strength at room temperature, while at higher temperatures the Mg–12Gd–3Y–0.5Zr alloy exhibited the maximum yield strength and ultimate tensile strength. The yield strength and ultimate tensile strength of the Mg–12Gd–3Y–0.5Zr alloy increased with the test temperature and showed its maximum at 150°C, and then decreased as the temperature increased further. The Mg–12Gd–3Y–0.5Zr alloy maintained a high ultimate tensile strength of more than 300MPa up to 250°C. The superior high temperature tensile strength of the tested alloy is mainly associated with solution strengthening and precipitation hardening of the cuboid-shaped phases and β′ precipitates in Mg matrix. Especially, β′ precipitates can hinder the dislocation movement at high temperature.