Effect of microstructure on wear behavior of Al–Mg–Si alloy matrix–10 vol.% Al2O3 composite

The wear resistance of under-aged and peak-aged 6061 Al–Al2O3 particulate composite has been investigated. Peak-aged composites were more wear-resistant than the under-aged composite, while the plane perpendicular to the extrusion direction was more wear-resistant than that parallel to the extrusion direction. The difference of the wear resistance between two different orientations was observed to be greater than that between under-aged and peak-aged matrix microstructures. It shows that preferential orientation of patriculates has a greater effect on the wear resistance than the change of the matrix microstructure. The difference of wear properties between two different orientations was explained by the effect of preferentially orientated reinforcing particles on the shear modulus and shear deformation. The shearing force on the plane perpendicular to the extrusion direction forces the volume beneath a rotating wheel to undergo semi-iso-shear-strain deformation, which requires greater force. The greater resistance to shearing force of the plane perpendicular to the extrusion direction would delay the plastic flow and subsurface damage, which improves the wear resistance.