Nanomechanics of Mg-Al intermetallic compounds

Cold spraying of pure Al powder on a pure Mg substrate together with subsequent post-spray annealing treatment produced Mg₁₇Al₁₂ (β-phase) and Mg₂Al₃ (γ-phase) intermetallic layers on the surface of the substrate. These layers showed significantly better nanomechanical properties, including the reduced elastic modulus and nanohardness, which were determined using nanoindentation, than commercial purity Mg and AZ91 alloys. Combined with their improved corrosion resistance, it is believed that both the γ-phase and the β-phase layers can provide effective protection of Mg alloys from wear and corrosion. The effect of post-spray annealing process on the formation of thick, uniform and dense intermetallic layers on pure Mg substrate was also investigated.