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Irradiation creates excess point defects in materials (vacancies and self-interstitial atoms), which can be eliminated by mutual recombination, clustering, or annihilation of preexisting defects in the microstructure, such as surfaces, grain boundaries, or dislocations. As a result, permanent irradiation sustains fluxes of point defects toward these point defect sinks and, in case of any preferential transport of one of the alloy components, leads to a local chemical redistribution. These radiation-induced segregation (RIS) phenomena are very common in alloys under irradiation and have important technological implications. Specifically in the case of austenitic steels, because Cr depletion at the grain boundary is suspected to be responsible for irradiation-assisted stress corrosion, a large number of experiments have been conducted on the RIS dependence on alloy composition, impurity additions, irradiation flux and time, irradiation particles (electrons, ions, or neutrons), annealing treatment before irradiation, and nature of grain boundaries. 1–5

The first RIS models generally consisted of application of Fick’s laws to reproduce two specific effects of irradiation: diffusion enhancement due to the increase of point defect concentration, and the driving forces associated with point defect concentration gradients. According to these models, RIS is controlled by kinetic coefficients D or L (defined below) relating atomic fluxes to gradients of concentration or chemical potentials. It was shown that these coefficients are best defined in the framework of the thermodynamics of irreversible processes (TIPs) within the linear response theory. RIS models were then …