Multiscale modelling of radiation damage and phase transformations: The challenge of FeCr alloys

We review the experimental evidence of the non-monotonic behaviour of FeCr alloys versus Cr content, particularly under irradiation (ordering versus segregation tendencies, microstructure and phase evolution, hardening and embrittlement), together with the theoretical efforts done at the electronic and atomic level to interpret them. We summarize the achievements of the two interatomic potentials developed for this system and perform a careful scrutiny of their limitations. We emphasise the difficulties related to the study, at the atomic-level, of concentrated alloys and propose routes to overtcome them. Finally we advance some opinions regarding the crucial points that deserve further investigation in order to fully understand this important binary alloy, at the basis of the steels for current and future nuclear applications.