Atomistically informed dislocation dynamics simulations: application to dislocation-loop interactions in zirconium

Abstract

Neutron irradiation of zirconium alloys leads to the formation of high densities of small dislocation loops. Their interactions with gliding dislocations are responsible for hardening and early necking of the material. Multi-scale numerical simulations of the interactions between dislocations and loops are undertaken to predict the mechanical properties evolution of these materials due to irradiation. Molecular dynamics simulations are first performed to assess the critical ingredients needed for dislocation dynamics simulations. Appropriate models and associated coefficients are then introduced in dislocation dynamics simulations in order to reliably reproduce the dislocation line energy, the cross-slip process from basal to prismatic planes and the mobility of straight and jogged dislocations. Based on this parametrization, interactions between dislocations and loops are finally computed with the two numerical methods. Careful comparisons between the two types of simulations show qualitative and quantitative agreement, opening the path to investigations of irradiation effects at the grain scale through large scale dislocation dynamics simulations.