Development of interatomic potentials for Fe-Cr-Al alloy with the particle swarm optimization method

Abstract

Due to its potential application in nuclear cladding system, Fe-Cr-Al alloys have attracted significant interest recently. Thus, it is of importance to acquire the classical interatomic interaction potential in order to predict the mechanical behavior of FeCrAl structures at the microscopic scale. In this work, the particle swarm optimization method has been applied and improved to develop the interatomic potentials for Fe, Cr, Al unitary systems and Fe-Cr, Fe-Al binary systems. The potential parameters are fitted to experimental elastic constants, first principle calculated lattice information and defect formation energies with consideration of force matching. The developed Fe-Cr-Al ternary potentials are used to predict the phase stability region for FeCrAl ferrite alloys. The bulk modulus for the single crystal and the plastic behavior under grain boundary tensile stress are also modeled to find the influence of Cr and Al contents on the mechanical properties of FeCrAl alloys. The solutes Cr would improve the mechanical properties while high Al content would lead to poor elastic and plastic properties. The predictions from the newly developed potential are in good agreement with experimental results.