Fracture mechanisms.

The fracture mechanisms operating in metallic and ceramic materials are summarized and the ranges of stress and temperature in which each of them dominates are shown on a fracture map. Cleavage fracture is described from an atomic point of view, and its relations to plasticity are discussed. Ductile fracture is analyzed on the level of inclusions and voids using analytical and numerical methods for describing void growth and void coalescence. The Gurson model, which describes the constitutive behaviour of a voided plastic material, is discussed in relation to cell models and to experiments. Creep fracture is described on the level of grain boundary cavities and their diffusive growth mechanisms. The chapter on chemical effects comprises the segregation of foreign atoms to grain boundaries (temper embrittlement), hydrogen embrittlement and stress corrosion cracking. The paper is concluded by a chapter on fracture mechanics including elastic- plastic fracture mechanics, stable crack grow th, fast cracking and creep crack growth.