Simple bond-order-type interatomic potential for an intermixed Fe-Cr-C system of metallic and covalent bondings in heat-resistant ferritic steels

Journal Article · Sun Dec 28 04:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4904447· OSTI ID:22399178

Kumagai, Tomohisa; Nakamura, Kaoru; Yamada, Susumu; Ohnuma, Toshiharu ^[1]

---

1. Materials Science Research Laboratory, Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan)

It is known that M{sub 23}C{sub 6}(M = Cr/Fe) behavior in heat-resistant ferritic steels affects the strength of the material at high temperature. The ability to garner direct information regarding the atomic motion using classical molecular dynamics simulations is useful for investigating the M{sub 23}C{sub 6} behavior in heat-resistant ferritic steels. For such classical molecular dynamics calculations, a suitable interatomic potential is needed. To satisfy this requirement, an empirical bond-order-type interatomic potential for Fe-Cr-C systems was developed because the three main elements to simulate the M{sub 23}C{sub 6} behavior in heat-resistant ferritic steels are Fe, Cr, and C. The angular-dependent term, which applies only in non-metallic systems, was determined based on the similarity between a Finnis-Sinclair-type embedded-atom-method interatomic potential and a Tersoff-type bond-order potential. The potential parameters were determined such that the material properties of Fe-Cr-C systems were reproduced. These properties include the energy and lattice constants of 89 crystal structures; the elastic constants of four realistic precipitates; the bulk moduli of B1, B2, and B3 crystals; the surface energies of B1 and B2 crystals; and the defect-formation energies and atomic configurations of 66 Fe-Cr-C complexes. Most of these material properties were found to be reproduced by our proposed empirical bond-order potentials. The formation energies and lattice constants of randomly mixed Fe-Cr alloys calculated using the interatomic potentials were comparable to those obtained through experiments and first-principles calculations. Furthermore, the energies and structures of interfaces between Cr carbide and α-Fe as predicted through first-principles calculations were well reproduced using these interatomic potentials.

• OSTI ID: 22399178
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 24 Vol. 116; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BONDING
CARBIDES
CARBON COMPLEXES
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
COVALENCE
CRYSTALS
FERRITIC STEELS
FORMATION HEAT
HEAT RESISTING ALLOYS
INTERFACES
LATTICE PARAMETERS
MOLECULAR DYNAMICS METHOD
POTENTIALS
PRECIPITATION
SURFACE ENERGY