A homogenized microstructural approach to creep fracture

A two-dimensional nonlocal continuum model is proposed in this paper for cr eep damage in polycrystalline materials. Starting from previous micromechan ical modeling, a heuristic homogenization approach is adopted to derive a t heory for the macroscopic response. The model accounts for the main damage mechanisms (grain boundary sliding, nucleation, growth and coalescence of c avities along the grain boundaries) responsible for the creep fracture proc ess. The resulting constitutive law takes into account the nonlocalities ex pressed through the gradients of the stresses and the: damage variables. (C ) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier S AS.