Jonathan A. Salem

Elevated-temperature fracture resistances of monolithic and composite ceramics using chevron-notched bend tests

Complete information regarding the elevated temperature fracture resistances of structural ceramics is essential for useful application of these materials in heat engine components[l , 2]. Traditionally ceramics have been considered to fracture in a brittle catastrophic fashion and therefore have been characterized by the use of a single parameter such as plane strain fracture toughness, KIc. However, innovative experimental work done on aluminum oxide[3] indicated the existence of increasing fracture resistance with increasing crack extension, that is R-curve behavior. Subsequent discoveries of R-curve behavior in other types of structural ceramics have precluded the adequate description of the fracture resistance of ceramics by fracture toughness alone.