Microstructures and mechanical properties of Mg–8Gd–0.6Zr–xNd (x = 0, 1, 2 and 3 mass%) alloys

Mg–8Gd–0.6Zr–xNd (x=0, 1, 2 and 3 mass%) alloys were prepared by metal mould casting method, and the microstructures, age hardening responses and mechanical properties have been investigated. The microhardness of the as-cast alloys is increased with increasing Nd content. The age hardening behavior and mechanical properties are enhanced significantly by adding Nd element. The peak ageing hardness of the Mg–8Gd–0.6Zr–3Nd alloy is 103, it is about 1.3 times more than that of the Mg–8Gd–0.6Zr alloy. The aged Mg–8Gd–0.6Zr–3Nd alloy exhibits maximum ultimate tensile strength and yield strength, and the values are 271 and 205 MPa at room temperature, 205 MPa and 150 MPa at 250 C, respectively. Which are about 2 times higher than those of Mg–8Gd–0.6Zr alloy. The improved hardness and strength are mainly attributed to the fine dispersiveness of Mg5RE and Mg12RE precipitates in the alloy.