Crack resistance curves of alumina and zirconia at room temperature

Ceramic three-point bend specimens were pre-cracked in a displacement-controlled test in air at room temperature to form sharp cracks of different lengths. Critical stress intensity factors (K IC were then measured as a function of sharp crack length in a fast-fracture, load-controlled test. Crack resistance curves (K IC against crack length) were determined for three commercially pure aluminas of different grain size, a debased alumina...