Screw dislocation interaction with irradiation defect-loops in alpha-iron: evaluation of cross-slip effect using dislocation dynamics simulations

摘要

Plastic strain spreading in post-irradiated ferritic steels usually takes the form of wavy shear bands, where the mobile dislocations randomly interact with the radiation-induced, dispersed defect populations. In these conditions, it is believed that the dislocation/defect interactions are significantly affected by the ubiquitous, stochastic cross-slip mechanism. The cross-slip effect is assessed by means of specific three-dimensional nodal DD simulation setups, consistent with available experimental evidence of cross-slip activity in postirradiation straining conditions, at room temperature. A significant, cross-slip induced reduction of the effective dislocation/loop interaction strength is thereby evidenced, for various applied stress conditions and dislocation configurations. The corresponding, local interaction mechanisms are consistent with grain scale DD simulations results, in terms of post-irradiation plastic strain spreading.