| Abstract Scope |
We describe a unified, thermodynamically consistent model for irradiation creep, that combines dislocation glide and the stress-induced preferential absorption (SIPA) of point defects at dislocations. Central to the model is the premise that the dynamics of point defects such as interstitials and vacancies is controlled by temperature, while the dynamics of extended defects, among which dislocations are of prime relevance, is controlled by the configurational degrees of freedom which evolve on a much slower time scale than the kinetic-vibrational degrees of freedom and, as such, fall out of equilibrium with the point defect evolution. We present model predictions in comparison to thermal and irradiation creep data in copper, aluminum, and ferritic-martensitic steels, which suggest that conventional SIPA mechanisms alone are inadequate to explain the pronounced dependence of the irradiation creep rates on stress and temperature, necessitating nontrivial corrections to the SIPA dislocation climb rates. The implication of these results into the stress and temperature dependencies of dislocation climb will be discussed, along with identifying important experimental and computational data. |