The multiple beneficial effects of Al₂O₃ nanoparticle addition to cast magnesium based systems (followed by extrusion) were investigated, constituting either: (a) enhanced strength; or (b) simultaneously enhanced strength and ductility of the corresponding magnesium alloys. AZ31 and ZK60A nanocomposites containing Al₂O₃ nanoparticle reinforcement were each fabricated using solidification processing followed by hot extrusion. Compared to monolithic AZ31 (tension levels), the corresponding nanocomposite exhibited higher yield strength (0.2% tensile yield strength (TYS)), ultimate strength (UTS), failure strain and work of fracture (WOF) (+19%, +21%, +113% and +162%, respectively). Compared to monolithic AZ31 (compression levels), the corresponding nanocomposite exhibited higher yield strength (0.2% compressive yield strength (CYS)) and ultimate strength (UCS), lower failure strain and higher WOF (+5%, +5%, -4% and +11%, respectively). Compared to monolithic ZK60A (tension levels), the corresponding nanocomposite exhibited lower 0.2% TYS and higher UTS, failure strain and WOF (-4%, +13%, +170% and +200%, respectively). Compared to monolithic ZK60A (compression levels), the corresponding nanocomposite exhibited lower 0.2% CYS and higher UCS, failure strain and WOF (-10%, +7%, +15% and +26%, respectively). The capability of Al₂O₃ nanoparticles to enhance the properties of cast magnesium alloys in a way never seen before with micron length scale reinforcements is clearly demonstrated.
Keywords: AZ series; Al2O3 nanoparticles; ZK series; mechanical properties; microstructure.