CONTINUOUS CREEP CAVITY NUCLEATION BY STOCHASTIC GRAIN-BOUNDARY SLIDING

Creep cavitation in metals and ceramics is generally considered to occur by the nucleation, growth, and coalescence of grain-boundary cavities. By considering grain-boundary slidings as the process driving force, a stochastic model is proposed for continuous cavity nucleation in metals and ceramics subjected to creep loading. The nucleation rate is shown to be directly proportional to the number of grain-boundary sliding events. The dependence of the number of cavities on grain boundary sliding displacement, creep strain, and time are established and compared with available experimental data of alumina, copper, and copper alloys. This comparison supports the contention that creep cavity nucleation in metals and ceramics does originate from stochastic grain-boundary sliding. © 1990 Chapman and Hall Ltd.