Estimation of energy of cubic iron‐carbon nanoclusters by molecular mechanic method

Abstract

The energy of cubic iron‐carbon nanoclusters was evaluated using the method of molecular mechanics. The focus was on two types of interstitial sites: octahedral and tetrahedral, in which the carbon atoms can be located. The calculation results showed that in the surface layer of the face‐centered cubic nanocluster, all of the tetrahedral interstitial sites were energetically equivalent. If a carbon atom changes position between two tetrahedral interstices in the direction of the ⟨111⟩, it can occupy an energetically preferable position in octahedral interstitial space. The comparison of the nanoclusters energy between the cases of surface and subsurface location of the carbon atoms in the octahedral interstice showed that the system has lower energy in the former case. For body‐centered cubic nanocluster, octahedral interstitial sites are more energetically favorable for carbon atoms than the tetrahedral interstice, excluding the surface. However, the octahedral interstitial sites on the surface are more preferable than tetrahedral interstice. Based on the calculations it was found that body‐centered cubic and face‐centered cubic nanoclusters could be unstable by the volumetric concentration of carbon.