Grain Size Dependence of Creep Lifetime Modeled by Means of Cellular Automata

Grain size dependence of creep is a complex relation. It can be increasing, decreasing or constant function accordingly to current conditions and material. It is a consequence of complex nature of microscopic mechanisms affecting creep. Some of them are analyzed in current paper by means of multiscale model, using simulation of damage development done by cellular automata technique. It was shown that enlarged sizes of grains, which promote development of intergranular microcracks, are compensated by reduced density of voids forming vacancies. Obtained in simulations grain size dependency follows experimentally observed dependency for small grains in dislocation creep range.