Metallic-covalent interatomic potential for carbon in iron

Derek J. Hepburn, Graeme J. Ackland

Research output: Contribution to journalArticlepeer-review

Abstract

Existing interatomic potentials for the iron-carbon system suffer from qualitative flaws in describing even the simplest of defects. In contrast to more accurate first-principles calculations, all previous potentials show strong bonding of carbon to overcoordinated defects (e.g., self-interstitials, dislocation cores) and a failure to accurately reproduce the energetics of carbon-vacancy complexes. Thus any results from their application in molecular dynamics to more complex environments are unreliable. The problem arises from a fundamental error in potential design-the failure to describe short-ranged covalent bonding of the carbon p electrons. We describe a resolution to the problem and present an empirical potential based on insights from density-functional theory, showing covalent-type bonding for carbon. The potential correctly describes the interaction of carbon and iron across a wide range of defect environments. It has the embedded atom method form and hence appropriate for billion atom molecular-dynamics simulations.

Original languageEnglish
Article number165115
Pages (from-to)-
Number of pages6
JournalPhysical review B: Condensed matter and materials physics
Volume78
Issue number16
DOIs
Publication statusPublished - Oct 2008

Keywords

  • MOLECULAR-DYNAMICS SIMULATIONS
  • ALPHA-IRON
  • TRANSITION-METALS
  • ELECTRON-IRRADIATION
  • COMPUTER-SIMULATION
  • FE
  • IMPURITIES
  • MODEL
  • INTERSTITIALS
  • TEMPERATURE

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