The interactions between dislocations and displacement cascades in FeCoCrNi concentrated solid-solution alloy and pure Ni

Abstract

Concentrated solid-solution alloys (CSAs) have been proposed as structural materials for advanced nuclear reactors due to their great irradiation tolerance. We studied and compared the interaction processes of displacement cascades and edge dislocations in FeCoCrNi CSA and pure Ni by molecular dynamics to explore the influence of dislocations on the irradiation resistances of CSAs. The edge dislocations preferentially absorb interstitials in both materials, however, the differences between the numbers of absorbed interstitials and vacancies in FeCoCrNi are smaller than in Ni, which is attributed to the smaller difference of mobilities of interstitials and vacancies in FeCoCrNi. When the centers of displacement cascades coincide with edge dislocations, the numbers of absorbed interstitials and vacancies in edge dislocations of FeCoCrNi are essentially the same, which is independent with PKA energies. The amounts of survived interstitials and vacancies in the matrix of FeCoCrNi are closer than that in pure Ni, which would avoid the formation of numerous large vacancy clusters induced by excessive vacancies. Furthermore, the edge dislocations are enriched with Ni, Co and depleted with Fe, Cr after interactions with displacement cascades, which is consistent with experimental results. The molecular dynamics simulation results of current study reveal that the edge dislocations in CSAs can probably serve as weak biased sinks for the annihilation of irradiation-induced defects and enhancing the irradiation resistances of CSAs.