Mechanical Behavior of a Magnesium Alloy Nanocomposite Under Conditions of Static Tension and Dynamic Fatigue

In this paper, the intrinsic influence of nano-alumina particulate (Al₂O_3p) reinforcements on microstructure, microhardness, tensile properties, tensile fracture, cyclic stress-controlled fatigue, and final fracture behavior of a magnesium alloy is presented and discussed. The unreinforced magnesium alloy (AZ31) and the reinforced composite counterpart (AZ31/1.5 vol.% Al₂O₃) were manufactured by solidification processing followed by hot extrusion. The elastic modulus, yield strength, and tensile strength of the nanoparticle-reinforced magnesium alloy were noticeably higher than the unreinforced counterpart. The ductility, quantified by elongation-to-failure, of the composite was observably lower than the unreinforced monolithic counterpart (AZ31). The nanoparticle-reinforced composite revealed improved cyclic fatigue resistance over the entire range of maximum stress at both the tested load ratios. Under conditions of fully reversed loading (R = ?1) both materials showed observable degradation in behavior quantified in terms of cyclic fatigue life. The conjoint influence of reinforcement, processing, intrinsic microstructural features and loading condition on final fracture behavior is presented and discussed.