Evaluating comparative wear behaviour of Al-15%Si based alloy/composites reinforced with zinc and zirconium oxide

ABSTRACT The tribological characteristics of stir cast Al-15%Si-10%Zn matrix with 15%ZrO2 reinforced composite were investigated. The microstructure of the Al-15Si alloy consisted of coarse primary Si and acicular eutectic Si phases randomly distributed in the Al dendrites. The Al-15%Si-10%Zn/ZrO2 composite showed spherical Si with a size between 25 and 75 µm; fragmented eutectic Si phase and uniform dispersion of ZrO2 particles in the matrix. The wear test was conducted using in a pin-on-disc method at different loads and sliding velocities. It was found reduced coefficient of friction, significant increase in the hardness and wear resistance of the composite compared to the matrix alloy. High wear resistance in the composite due to the effect of solid lubrication provided by Zn, and good fracture toughness and wear resistance by the reinforced ZrO2 particles. The predominant oxidative and abrasive wear were identified as the mechanisms leading to material failure through plastic deformation and delamination. GRAPHICAL ABSTRACT