Abstract
Quasistatic indentation has been used to study the hardness and fracture toughness of advanced ceramic materials and has been used as the starting point for the modelling of many wear situations. A lack of data on the nature of subsurface cracks in ceramics has resulted in limited evidence to indicate that crack systems generated by indentation bear any relationship to complex wear situations. In the current study, the technique of confocal scanning laser microscopy (CSLM) has been used to obtain subsurface information on a fine-grained alumina ceramic. The alumina has been indented and CSLM has been used to obtain a substantial amount of data on both surface and subsurface cracking. The data have been compared with predictions from existing theories and it has been shown that the subsurface lateral cracking can be predicted by measuring the more easily observable radial cracks. Radial cracking and subsurface damage due to indentation have proved to be similar to that produced by single particle ballistic impact; hence it may be possible to predict erosive wear rates by conducting simple indentation studies.