Atomistically informed irradiation induced hardening model for zirconium

Neutron irradiation of zirconium alloys leads to the formation of dislocation loops. Their interactions with gliding dislocations are responsible for hardening. Multi-scale numerical simulations of interactions between dislocations and loops are undertaken to predict the mechanical properties evolution of these materials due to irradiation and during post-irradiation annealing. The effect of loop size and density on the resulting hardening is systematically investigated using molecular dynamics simulations. Dislocation dynamics simulations, originally calibrated on molecular dynamics simulations, are used to extrapolate the results to larger loop and box size. It is shown that the larger the loop the higher the hardening. An analytical hardening model, originally based on dislocation and precipitate interactions, is proposed. It is able to reproduce very well the hardening induced by loops in a wide range of loop size and density.