Fe–Ni many-body potential for metallurgical applications

Abstract

A many-body interatomic potential for the Fe–Ni system is fitted, capable of\ndescribing both the ferritic and austenitic phase. The Fe–Ni system exhibits\ntwo stable ordered intermetallic phases, namely, L10 FeNi and L12 FeNi3,\nthat are key issues to be tackled when creating a Fe–Ni potential consistent\nwith thermodynamics. A procedure, based on a rigid lattice Ising model\nand the theory of correlation functions space, is developed to address all the\nintermetallics that are possible ground states of the system. While controlling\nthe ground states of the system, the mixing enthalpy and defect properties\nwere fitted. Both bcc and fcc defect properties are compared with density\nfunctional theory calculations and other potentials found in the literature.\nFinally, the potential is thermodynamically validated by constructing the alloy\nphase diagram. It is shown that the experimental phase diagram is reproduced\nreasonably well and that our potential gives a globally improved description of\nthe Fe–Ni system in the whole concentration range with respect to the potentials\nfound in the literature.