Atomic-scale modeling of clear band formation in FCC metals

Molecular Dynamics simulations are employed to simulate at the atomic scale the interactions between dislocations and several irradiation defects in FCC crystals: glissile interstitial loops, stacking fault tetrahedra and interstitial Frank loops. The simulations reveal different interaction mechanisms (absorption, unfaulting and shear), depending on the nature and shape of the defects and show that athermal cross-slip events are systematically involved when screw dislocations are considered. In the case of Frank loops, the classical unfaulting mechanism is observed but is not the general rule, defect shearing being more frequent than usually assumed. Consequences of these observations on clear band formation are discussed.