Molecular Dynamics Modelling of Liquid Fe-C Alloys

Abstract

Properties and structure of liquid Fe-C alloys with carbon concentration up to 20 at% at temperatures up to 2500 K were calculated using molecular dynamics modelling. Interaction between Fe-Fe and Fe-C atoms was described using the embedded atom potential (EAM). The Morse potential was chosen for Fe-C pair interaction, while C-C pair interaction was presented in the form of the repul- sive potential. Parameters of potentials were adjusted using experimental data for density, internal energy, bulk modulus and distance between Fe and C atoms in liquid Fe-C alloys near the liquidus temperature. Calculated density and molar volume of Fe-C alloys at 1873 K decreased with increasing carbon concentration; a temperature coefficient of density of liquid alloys was, practically, independent of the carbon concentration. Carbon content of the alloys had a negligible effect on the distance between Fe-Fe and Fe-C atoms and on a sum of coordination numbers Fe-Fe and Fe-C. Distribu- tion of atoms in the first coordination sphere in the Fe-C alloys was close to statistical.