Investigation of radiation temperature and straining temperature effects on the screw dislocation mobility evolution in irradiated ferritic grains using 3D dislocation dynamics

Abstract : Nuclear structural materials subjected to neutron irradiation accumulate dose-dependent, disperse defect clusters populations. Subsequent dislocation/defect interactions induce material mechanical property degradations, including hardening and embrittlement. Our goal in this work is to evaluate the effect of disperse defect clusters population on the effective dislocation mobility in ferritic Fe-Cr grains, using 3D dislocation dynamics simulations. The defect induced changes of the grain-scale mechanical response are evaluated using the recently proposed Defect-Induced Apparent Temperature (DIAT) shift concept. It is found that the DIAT shift associated with a given defect dispersion scales with the ductile to brittle transition temperature (DBTT) shift associated with exactly the same, observed defect population. The dose-dependent evolutions associated with broad irradiation temperature and straining temperature changes are investigated herein, for further exploration and validation of the DIAT shift concept.