Structural, elastic and thermal properties of cementite (Fe$_3$C) calculated using Modified Embedded Atom Method

TL;DR

This study develops a Modified Embedded Atom Method potential for Fe-C alloys to accurately predict the structural, elastic, and thermal properties of cementite, validated against experimental and first-principles data.

Contribution

It introduces a new MEAM potential for Fe-C alloys that reproduces cementite's properties and investigates its stability and thermal behavior through molecular dynamics simulations.

Findings

Predicted elastic constants agree with experimental data.

Calculated surface formation energies match first-principles results.

Simulated melting temperature and thermal properties align with experimental observations.

Abstract

Structural, elastic and thermal properties of cementite (Fe$_3$C) were studied using a Modified Embedded Atom Method (MEAM) potential for iron-carbon (Fe-C) alloys. Previously developed Fe and C single element potentials were used to develop an Fe-C alloy MEAM potential, using a statistically-based optimization scheme to reproduce structural and elastic properties of cementite, the interstitial energies of C in bcc Fe as well as heat of formation of Fe-C alloys in L$_{12}$ and B$_1$ structures. The stability of cementite was investigated by molecular dynamics simulations at high temperatures. The nine single crystal elastic constants for cementite were obtained by computing total energies for strained cells. Polycrystalline elastic moduli for cementite were calculated from the single crystal elastic constants of cementite. The formation energies of (001), (010), and (100) surfaces of cementite were also calculated. The melting temperature and the variation of specific heat and volume with respect to temperature were investigated by performing a two-phase (solid/liquid) molecular dynamics simulation of cementite. The predictions of the potential are in good agreement with first-principles calculations and experiments.