Irradiation hardening by interstitial loops: atomistic study and micromechanical model

We present molecular dynamics simulations of the interactions between glissile interstitial loops and an edge dislocation in a fcc nickel crystal. This study shows atomic-scale reactions leading to a pinning of the dislocation by the loops which are dragged along when the dislocation unpinns. This atomic-scale information is incorporated in a micromechanical model. Predictions of the model at the micron scale are compared to the initial hardening and subsequent softening of irradiated specimens observed experimentally in traction tests.