Corrosion Behavior of Squeeze Cast Mg Alloy AM60-Based Hybrid Nanocomposite

Micron-sized alumina (Al₂O₃) short fibre and/or nano-sized alumina (Al₂O₃) particles were squeezed cast into Mg AM60 alloy. Two types of 7 vol.% Fibre/AM60, and (7 vol. % Fibre + 3 vol.% nano-particle)/AM60 composites, as well as the unreinforced matrix alloy were prepared. The corrosion behaviors of the composites as well as the unreinforced matrix alloy were investigated by using the potential dynamic polarization test. Compared with the matrix alloy, the introduction of micron-sized alumina fibres decreased the corrosion resistance of Mg alloy AM60 considerably due to the presence of excessive interfaces between the fibre and matrix. The high density of grain boundaries and the absence of noble precipitates such as β-Mg₁₇Al₁₂ phases and Al–Mn intermetallics at the grain boundaries in the composites should be for the reduction in their corrosion resistance. The addition of the nano-sized particles led to almost no further reduction in the corrosion resistance of the composite.