Utilization of Microalloying with Rare Earth Elements and Hot Extrusion for Remarkable Grain Refinement and Enhancement of Mechanical Properties of as-Cast Magnesium Alloy

The effects of micro-addition by rare earth (re) elements (via cerium-based mischmetal) and hot deformation (via extrusion process) on the microstructure and mechanical properties of mg- 0.5zn-0.5zr alloy were studied. optical microscopy, scanning electron microscopy (sem), energy-dispersive spectroscopy (eds), and tensile testing were used for characterization of alloys in the as- cast and wrought conditions. it was found that the addition of 0.5 wt% re combined with the hot extrusion process could remarkably refine the grain size from 1320 µm for the as-cast mg-0.5zn-0.5zr alloy to the recrystallized grain size of 1.3 µm for the extruded mg- 0.5zn-0.5zr-0.5re alloy. compared to the as-cast counterparts, the ultimate tensile strength (uts) and total elongation to failure were significantly enhanced by the extrusion process. quantitatively, the uts of ~ 300 mpa with the total elongation of ~ 18% was obtained for the extruded mg-0.5zn-0.5zr-0.5re alloy, which reveals the favorable effects of the ultra grain refinement on the enhancement of the mechanical properties of magnesium alloys.