Abstract
The technique of a V-shaped notch with very sharp root radius was used with the single-edge notched beam and chevron notch methods to evaluate fracture toughness of ceramics. These methods are improved techniques using a V-shaped diamond wheel. The single-edge precracked beam and chevron notch techniques were also compared for gas-pressured Si3N4. The fracture toughness showed quite small scatters and coincided with one another quite well, except for the usual chevron notch method. 11 refs.