COMPOSITE MODELING OF STRESS CHANGE RESPONSE IN STEADY-STATE CREEP

A detailed model of creep behaviour of heterogeneous structures consis ting of hard and soft regions is presented. It is based on the paramet ers of dislocation structure (density of dislocations in the interior of subgrains, subgrain size, and subgrain misorientation) and yields t he steady-slate values of the local stresses. The model is used to sim ulate the response to sudden stress changes. The apparent activation a rea, the constant structure stress exponent, and the internal stress a re determined and compared with experimental data for aluminium.