High temperature mechanical behavior of low-pressure sand-cast Mg–Gd–Y–Zr magnesium alloy

The aim of this work is firstly to optimize T6 heat-treatment of low-pressure sand-cast Mg–10Gd–3Y–0.5Zr alloy, and then systematically investigate the mechanical behavior of the T6-treated alloy from room temperature to 300 °C. It turned out that the optimum T6 heat-treatments for the tested alloy are 525 °C × 12 h + 225 °C × 14 h and 525 °C × 12 h + 250 °C × 12 h which integrated age-hardening and tensile properties into account, respectively. The strength of the T6-treated alloy indicates obvious anomalous temperature dependence from room temperature to 300 °C, namely both ultimate tensile strength and yield strength of the tested alloy firstly increase with tensile temperature, and then decrease as temperature increases further. Elongation increased with temperature monotonously. The tensile fracture mode of the tested alloy changes from transgranular fracture to intergranular fracture with the increasing of test temperature. Keywords: Mg–Gd–Y–Zr, Heat treatment, High temperature tensile property, Anomalous temperature dependence