An indentation model for erosive wear in Al2O3/SiC nanocomposites

The erosive wear resistance of Al2O3 has been shown to be improved by the addition of 5 vol.% of sub-micron sized SiC particles to form a ‘nanocomposite’, in agreement with previous results. The erosive wear was measured directly, and also estimated by an indentation model consisting of closely spaced grids of indentations that mimic the effect of successive particle impacts; in the model, particle impacts cause sub-surface cracking but loss of material from the surface occurs only from an impact within a region damaged by a previous impact. The volume of material lost from within indentation grids was used to predict the wear rate. These predictions agreed well with the directly measured values.The commonly observed change in fracture mode from intergranular for Al2O3 to transgranular for nanocomposites was confirmed. Transgranular fracture can allow a smaller volume of material to be removed during an impact and hence increase erosion resistance.