The surface fracture behavior of a high-purity, high-density alumina, as a
function of grain size (3, 5, and 9 mu m), was investigated using an indent
ation-fatigue technique. Increasing the grain size reduced the threshold fo
r crack nucleation, reduced the resistance to surface spalling, and increas
ed the volume of materials lost per spalling event. These results are expla
ined in terms of residual stresses and fatigue damage.