The strong hardening effect of Re segregation on edge dislocation lines in W

Abstract

We investigate the radiation hardening induced by the segregation of solute Re atoms along edge dislocation lines in W. Given the Re content and the irradiation temperature (which are chosen to represent both ITER and DEMO conditions), reference atomic configurations are first obtained with Metropolis Monte Carlo, where the equilibrium Re content at the dislocation core is evaluated. Next, the critical unpinning shear stress is evaluated with a molecular dynamics tool and the classical method of Barnett et al. The study reveals that the effect of Re segregation is strong, its magnitude could be compared with the pinning effect of other radiation defects such as nanovoids, dislocation loops and Re-rich precipitates formed in bulk. This form of hardening is therefore important and should be taken into account in higher scale models.