Carbon–vacancy complexes as traps for self-interstitial clusters in Fe–C alloys

Self-interstitial loops in irradiated Fe–C alloys are formed by the growth of small self-interstitial atom clusters created directly in cascades. For these clusters to grow up to visible sizes they should be stopped by traps otherwise they would disappear in sinks due to their high one dimensional mobility. The well-known affinity of carbon with vacancies in α-Fe leads to the formation of carbon–vacancy (C–V) complexes that are potential candidates as traps for SIA loops. Applying molecular static simulations we have studied the interaction between the most abundant C–V complexes and SIA clusters using a metallic covalent interatomic model for the Fe–C system. The complexes studied, {Cn–Vm}, are C–V, C–V2 and C2–V. The maximum binding energies obtained for the interaction with a 1/2 〈1 1 1〉 61SIA cluster are 0.75 eV for the C–V, 1.4 eV for the C–V2 and 1.5 eV for C2–V. Finally, additional MD simulations were used to check the stability of the traps at high temperature.