A PROBABILISTIC MODEL FOR THE GROWTH OF CREEP CRACKS

We present here a model for creep crack growth in which the primary me chanism for crack extension is the coalescence of the crack with adjac ent voids. Tile model incorporates several key probabilistic features, notably random placement of the voids along the grain boundary, and r andom values for the grain boundary and seif-diffusivities. The predic tions of the model are in good agreement with C-controlled crack grow th data for type 304 stainless steel at lower C values. However, the agreement with K-controlled crack growth data for Inconel-718 is poor, possibly because crack growth in this material occurs by a different mechanism than that postulated here. (C) 1997 Elsevier Science Ltd.