Effect of radiation-induced segregation on the point-defect absorption by surfaces, dislocations, and cavities in dilute BCC Fe-based alloys

Abstract

The evolution of microstructures under irradiation is driven by the interaction of point defects (PDs) with structural sinks, such as surfaces, dislocations, and cavities. This study investigates the effect of solute radiation-induced segregation (RIS) on the sink strengths of these defects in dilute BCC Fe-based alloys containing Cr, Cu, Si, and Ni. Using the Onsager formalism, PD and solute fluxes were computed to derive sink strengths and absorption biases as functions of solute concentration. The results reveal that adding Cu, Si, and Ni significantly reduces sink bias, with Ni having the strongest impact. Unlike pure Fe, surfaces in Fe-X alloys exhibit a vacancy absorption preference. Notably, Ni decreases dislocation and cavity biases, altering the point-defect absorption preference of cavities at high Ni concentrations. Applying these findings to a mean-field rate model provides insights into the cavity growth of Fe-based alloys under irradiation, in line with available experimental observations.