Effects of Grain Size on Strength and Fracture Toughness in Alumina

Abstract

Three-point bending and fracture toughness tests of alumina specimens with various grain sizes were carried out to discuss the effects of grain size on bending strength and fracture toughness. The bending strength increased with reducing grain size. The valid fracture toughness is independent of grain size. On the other hand, the apparent fracture toughness with slow crack growth increased with increasing grain size due to the R-curve behavior.