Microstructure and mechanical properties of Mg–Gd–Dy–Zn alloy with long period stacking ordered structure or stacking faults

The Mg–6.5Gd–2.5Dy–1.8Zn (wt.%) alloy with high strength and ductility was prepared by conventional casting method. At room temperature, the as-cast alloy with 14H long period stacking ordered (LPSO) structure exhibits an ultimate tensile strength of 276 MPa and elongation to failure of 10.8%, while they are 392 MPa and 6.1% for the peak-aged alloy with basal plane stacking faults (SF). The results indicate that the kinking of LPSO structure is beneficial for both work hardening and plasticity, and 14H LPSO structure contributes more to the improvement of ductility while SF is more effective in increasing strength.

► A new Mg–Gd–Dy–Zn alloy with high strength and ductility was prepared by conventional metal mould casting method.
► The as-cast sample with 14H long period stacking ordered (LPSO) structure exhibits acceptable strength and high ductility.
► The peak-aged sample with basal plane stacking faults (SF) shows high strength and adequate elongation.