Crack formation criterion for superplastic tensile failure in oxide ceramics

Abstract

Tensile failure in superplastic oxide ceramics are investigated on the basis of microstructural analysis and damage models. The results reveal a close similarity between superplastic tensile failure in fine-grained ceramics and ductile failure in metallic materials containing microvoids or hard inclusions. Detailed discussion will be given concerning the comparison with earlier analyses that assume brittle crack-propagation and/or the existence of a critical grain size for failure.