Interatomic potentials and defect properties of Fe–Cr–Al alloys

Abstract

Fe–Cr–Al alloys have the potential to form a crucial class of enhanced accident tolerant fuel cladding materials in light water reactor due to their excellent oxidation resistance in high temperature steam environments. The irradiation resistant performance is also significant for the development and application of fission and fusion reactor materials. In this work, we developed a Fe–Cr–Al interatomic potential based on the Finnis–Sinclair (F–S) formulism, which can be used to describe the defect properties in Fe–Cr–Al alloys. The potential parameters for Fe–Cr–Al alloys were determined by fitting to a set of experimental results and density functional theory (DFT) calculations. Specifically, the formation energies of self–interstitial atoms and the stacking fault energy obtained from the present Al potential are consistent with the DFT results. The point–defect properties of Fe–Cr and Fe–Al alloys determined with the DFT calculations, such as the mixed (both Fe–Cr and Fe–Al) or pure (both Cr–Cr and Al–Al) dumbbells and the substitutions (both Cr and Al atoms) in the body–centered cubic (bcc) Fe matrix, are well reproduced by our atomistic simulations. Consequently, this parameterized potential is expected to be capable for atomistic simulations of irradiation defects and defect evolution in Fe–Cr–Al ternary systems.