Effects of dislocation network on radiation damage in iron investigated by molecular dynamics method

Abstract

Effects of dislocation networks on the evolution of displacement cascades and related mechanical properties and void swelling in BCC-Fe are investigated at atomic scale through molecular dynamics simulations. An atomistic model containing dislocation networks is built based on a coupled method developed in this work. Formation of more sub-cascades, strong biased absorption of interstitials, formation of more vacancies, and existence of pinned 1/2<111> interstitial loops are explored, which may be induced by inhomogeneous stress fields and related changes of dislocation network-defect interactions. The ultimate tensile and shear stresses of the dislocation network model are only slightly affected by multiple cascades, while void swelling is higher than that obtained in a perfect lattice under the same conditions. Thus, the effects of dislocation networks provide new understanding for some experimental results and should be considered in meso/macro-scale simulations to obtain more reliable results.