High Temperature Mechanical Properties of Sand-Cast Mg-Gd-Y Magnesium Alloy

In the present work, T6 heat treatment (solution treatment and subsequent aging) of the sand-cast Mg–10Gd–3Y–0.5Zr (wt.%) alloy was optimized by measuring both hardness vs aging time process curves and tensile properties of the differently T6 treated alloys at room temperature. Then the high temperature tensile properties of the studied alloys at the optimum T6 heat treatment were investigated systematically. The temperature range of the tensile tests was 25 °C to 300 °C. The results show that the optimum T6 heat treatment for sand-cast Mg–10Gd–3Y–0.5Zr alloy is 525°C×12h+250°C×10h. The T6 treated alloy exhibits significant anomalous strength behaviour from 25 °C to 300 °C, i.e., both tensile yield strength and ultimate tensile strength of the studied alloy first increased with increasing of temperature, and then decreased as the temperature increased further. Comparatively, elongation increased continuously with increasing temperature.