Roles of porosity, residual stresses and grain size in the fracture of brittle solids

Abstract

The effects of porosity, grain size and residual stresses on the thermal shock resistance and the strength of brittle solids are treated employing the stress intensity factor approach. Maximum resistance to thermal shock is found for materials possessing small pores and relatively large pre-existing cracks. The theory shows that it should be possible to synthesize a brittle material with high strength without the need to reduce the grain size significantly, provided that the grain size is considerably smaller than the flaw size. Excellent agreement was obtained between predicted and experimental values for strength.