A micromechanical model is developed to describe effects such as combined power law creep and diffusion, grain boundary sliding and cavitation in polycrystals. Several aspects of creep constrained cavitation are taken into account such as diffusion in cage of creeping matrix material and cavitating facets in a cage of creeping grains. Grain boundary sliding is modelled by distributed micro-shearcracks. It is shown that the different physical mechanisms and their interactions are functions of a well defined material parameter #lambda#, which can be related to the material length scale L introduced by Rice (1981).
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