In the present study, room temperature mechanical properties of pure magnesium, Mg/ZrO₂ and Mg/(ZrO₂ + Cu) composites with various compositions are investigated. Results revealed that the use of hybrid (ZrO₂ + Cu) reinforcements in Mg led to enhanced mechanical properties when compared to that of single reinforcement (ZrO₂). Marginal reduction in mechanical properties of Mg/ZrO₂ composites were observed mainly due to clustering of ZrO₂ particles in Mg matrix and lack of matrix grain refinement. Addition of hybrid reinforcements led to grain size reduction and uniform distribution of hybrid reinforcements, globally and locally, in the hybrid composites. Macro- and micro- hardness, tensile strengths and compressive strengths were all significantly increased in the hybrid composites. With respect to unreinforced magnesium, failure strain was almost unchanged under tensile loading while it was reduced under compressive loading for both Mg/ZrO₂ and Mg/(ZrO₂ + Cu) composites.
Keywords: X-ray diffraction; mechanical properties; metal matrix composites; microstructure; microwave sintering; scanning electron microscopy.