Excellent ductility and strong work hardening effect of as-cast Mg-Zn-Zr-Yb alloy at room temperature

In this paper, we report a new single phase solid solution as-cast Mg-1Zn-0.4Zr-0.2Yb alloy that possesses excellent ductility (δ_f = 38.5%) and strong work hardening effect (n = 0.38) at room temperature. The low stacking fault energy (SFE) in Mg-1Zn-0.4Zr-0.2Yb alloy might be due to the addition of trace Yb, and the low SFE is conducive to improving the activity of basal dislocation slip, activations of non-basal dislocations slips and the formation of deformation twins during tensile deformation, eventually leading to the development of the ductility in Mg-1Zn-0.4Zr-0.2Yb alloy. The strong work hardening effect of Mg-1Zn-0.4Zr-0.2Yb alloy is due to the formation of stacking faults and deformation twins induced by low SFE, which can remarkably store dislocations, restrict dislocation motions and result in multiplication and storage of dislocations at twin boundaries.