Simulation of nanostructure evolution under helium implantation in Fe–(2.5–12.5)at% Cr alloys at a temperature of 343 K

Abstract

Characterization of helium-implanted Fe–(2.5–12.5)at% Cr alloys with the flux of 7 × 10–6 dpa/s at a temperature of 343 K has been performed by means of cluster dynamics simulations. We have suggested a model for simulating an Fe–C–Cr system under helium implantation based on a selection of the latest data from atomistic studies and available experiments. Kinetics of carbon-vacancy and helium-vacancy complexes has been studied. Only one parameter is used to guarantee the best reproduction possible of experimental positron annihilation lifetime spectroscopy data for Fe–Cr alloys on dependences of vacancy cluster size on chromium content and irradiation dose via fitting. This is an effective binding energy of self-interstitial atoms to dislocation loops decorated by chromium atoms. It has a “snaky” dependence of chromium content with a minimum of about 9%Cr.