Residual-Stress-Induced Grain Pullout in a 96% Alumina

A comparison of the surface and bulk microstructures of two 96% aluminas indicates that the residual stresses arising from thermal expansion mismatch created by crystallization of the amorphous boundary phase, when combined with stresses created during grinding, can lead to excessive pullout of the alumina grains. However, neither source of residual stress is, by itself, sufficient to cause such pullout. Residual stresses resulting from crystallization of the boundary glass are expected to play a significant role in determining the abrasive wear resistance of these materials.