Stochastic aspects of creep cavitation in ceramics

Abstract

Creep fracture of ceramic materials frequently occurs by the nucleation, growth, and coalescence of grain boundary cavities. Recent experimental studies of cavitation kinetics in compression crept ceramics, supported by micromechanical modeling, have identified a number of stochastic aspects of cavitation. The stochastic nature of cavitation arises primarily due to the dependence of both cavity nucleation and cavity growth on grain boundary sliding. A degree of randomness is also imposed by the nonuniform distribution of potential nucleation sites. Pertinent experimental results and micromechanical models are briefly presented and used to support the important role of grain boundary sliding. A stochastic model of grain boundary sliding is then proposed by considering the sliding events to occur as an inhomogeneous Poisson process. Implications of the stochastic nature of cavitation are then discussed in terms of the cavity nucleation, growth, and coalescence processes.