Effect of C on vacancy migration in α-iron

  • Chu Chun Fu
  • , E. Meslin
  • , A. Barbu
  • , F. Willaime
  • , V. Oison

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Carbon atoms are always present in Fe-based materials, either as impurities even in high purity samples or as an intrinsic constituent in steels. Density Functional Theory calculations have been performed to study the interaction between C atoms and vacancies (V) in α-Fe. We find that the formation of VCn complexes is energetically favourable for n ≤ 3, with VC2 being the most stable one. The energy gain corresponding to the clustering reaction VCn-1 + C → VCn depends mainly on the strength of C-C covalent bonds. The vacancy diffusivity is shown to be significantly modified by the formation of vacancy-carbon complexes, exhibiting non-Arrhenius behaviour. Effective vacancy diffusion coefficients in α-Fe are calculated as a function of temperature and carbon content using a simplified thermodynamic model. The results are discussed in detail in the limiting case of excess of C with respect to vacancies.

Original languageEnglish
Title of host publicationTheory, Modeling and Numerical Simulation of Multi-Physics Materials Behavior
EditorsVeena Tikare, Graeme E. Murch, Frederic Soisson, Jeung Ku Kang
PublisherTrans Tech Publications Ltd
Pages157-164
Number of pages8
ISBN (Print)9783908451563
DOIs
Publication statusPublished - 1 Jan 2008
Externally publishedYes
EventSymposium on Theory, Modeling and Numerical Simulation of Multiphysics Behavior, 2007 - Boston, United States
Duration: 26 Nov 200730 Nov 2007

Publication series

NameSolid State Phenomena
Volume139
ISSN (Print)1012-0394
ISSN (Electronic)1662-9779

Conference

ConferenceSymposium on Theory, Modeling and Numerical Simulation of Multiphysics Behavior, 2007
Country/TerritoryUnited States
CityBoston
Period26/11/0730/11/07

Keywords

  • Ab initio
  • Carbon
  • Diffusion
  • Equilibrium
  • Impurity
  • Iron
  • Irradiation
  • Kinetic
  • Thermodynamic

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