MODELING OF CREEP DAMAGE BY MULTIPLE CAVITY GROWTH ON GRAIN BOUNDARIES

摘要

An original approach to the problem of multiple cavity growth on grain boundaries under creep loading is proposed. Continuous nucleation of randomly distributed cavities and cavities coalescence are taken into account. A balance equation for the distribution of pore sizes is formulated and numerically solved. The cavity nucleation rate is assumed to be proportional to the creep rate. Cavities grow according to the classical axisymmetric solution as function of their respective size and the size of their influence zone. Cavity coalescence is taken into account by integral sink and source terms in the balance equation. The solution provides an estimate of the damage evolution, represented by the cavitated surface area and of the global thickening of the grain boundary.