Effects of Nd on microstructure and mechanical properties of as-cast Mg–12Gd–2Zn–xNd–0.4Zr alloys with stacking faults

In order to study the effects of Nd addition on microstructure and mechanical properties of Mg–Gd–Zn–Zr alloys, the microstructure and mechanical properties of the as-cast Mg–12Gd–2Zn–xNd–0.4Zr (x = 0, 0.5wt%, and 1wt%) alloys were investigated by using optical microscope, scanning electron microscope, X-ray diffractometer, nano indentation tester, microhardness tester, and tensile testing machine. The results show that the microstructures mainly consist of α-Mg matrix, eutectic phase, and stacking faults. The addition of Nd plays a significant role in grain refinement and uniform microstructure. The tensile yield strength and microhardness increase but the compression yield strength decreases with increasing Nd addition, leading to weakening tension–compression yield asymmetry in reverse of the Mg–12Gd–2Zn–xNd–0.4Zr alloys. The highest ultimate tensile strength (194 MPa) and ultimate compression strength (397 MPa) are obtained with 1wt% Nd addition of the alloy.