High strength yet ductile rare earth-containing magnesium alloy

Microstructure and tensile properties of Mg-2Zn (Z2), Mg-2Zn-0.3Ca (ZX20), and Mg-2Zn-4RE-0.3Ca alloys in the as-cast and wrought extruded conditions were investigated. Grain refinement via Ca addition improved the strength-ductility balance of ZX20 alloy; while the formation of dendritic microstructure with interdendritic network of RE-rich eutectics in ZEX240 alloy resulted in poor as-cast properties. However, a remarkable grain refinement by dynamic recrystallization (DRX) and fragmentation and dispersion of intermetallics were achieved after hot extrusion of the ZEX240 alloy, leading to a good combination of ultimate strength and ductility as well as a high yield stress of ∼253 MPa, outperforming other alloys. In this regard, the presence of Ce-containing particles promoted grain refinement and led to the improvement of the mechanical behavior.