Effects of Nd/Gd value on the microstructures and mechanical properties of Mg-Gd-Y-Nd-Zr alloys

Four Mg-Gd-Y-Nd-Zr alloys were prepared by mold casting to investigate the effects of Nd/Gd ratios on microstructures and mechanical properties. The as-cast alloys mainly consist of α-Mg and β-Mg5(GdYNd). Volume fractions of the second phase increase and grains were slightly refined with the rising Nd/Gd ratio, when the alloying addition is equal. Meanwhile, fibers of second phase also increase in the extruded alloys when the Nd/Gd value increases. However, the Nd/Gd ratio could hardly influence the mechanical properties of the extruded alloys. The aging hardening response of the extruded alloy differs due to different Nd/Gd ratios. The potential mechanisms have also been discussed in detail.