Ab-initio modeling of the short range order in Fe-N and Fe-C austenitic alloys

TL;DR

This study uses ab-initio calculations and Monte Carlo simulations to analyze the atomic short range order in nitrogenous austenite, revealing partial nitrogen atom ordering and the Fe6N phase formation.

Contribution

It introduces a novel combination of ab-initio and Monte Carlo methods to model short range order in Fe-N alloys, highlighting nitrogen atom partial ordering.

Findings

Nitrogen atoms can be partially ordered in FCC Fe lattice.

The Fe6N phase exhibits short range order among N atoms.

Atomic structure of nitrogenous austenite includes N atoms in the third coordination sphere.

Abstract

In the present paper, we have studied atomic structure of nitrogenous austenite. High precision ab-initio calculation was utilized for the calculation of the pair potentials of interatomic interactions N-N in FCC Fe lattice. These potentials were used for the Monte Carlo modeling of the short range order in the Fe-N system. It was discovered that in FCC Fe lattice, nitrogen atoms might be partially ordered. In this case, atomic structure of nitrogenous austenite is characterized by availability of the Fe6N phase with the short range order over the N atoms located in the third coordination sphere.