Enhancement of mechanical properties and corrosion resistance of Mg-Ca alloys through microstructural refinement by indirect extrusion

The effect of indirect extrusion on microstructural refinement, mechanical properties and corrodibility of the pure Mg and Mg-Ca alloys (up to 3 wt.% Ca) in Hank's solution has been systematically studied. After extrusion, mechanical properties including tensile strength and ductility, and corrosion resistance of the Mg-Ca alloys were greatly enhanced in the Mg-Ca alloys with Ca ⩾ 1%. Effective break-up of (semi-)continuous secondary phase (Mg2Ca) existing along grain boundaries or interdendritic regions during extrusion played a critical role in enhancement of the corrosion resistance of the Mg-Ca alloys with Ca ⩾ 1% compared to the as-cast counterparts.