Calculation of impurity diffusivities in α-Fe using first-principles methods

Shenyan Huang, Daniel L. Worthington, Mark Asta*, Vidvuds Ozolins, Gautam Ghosh, Peter K. Liaw

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

89 Scopus citations

Abstract

Self- and impurity diffusivities in body-centered-cubic (bcc) iron have been calculated within the formalisms of harmonic transition-state theory and the Le Claire nine-frequency model for vacancy-mediated diffusion. The approach combines first-principles calculations of vacancy formation, migration, and solute-binding enthalpies and entropies in the ferromagnetic phase, with an empirical relationship for the effect of magnetic disorder on diffusion activation energies. Calculated Fe self-diffusion and Mo and W impurity-diffusion coefficients are shown to agree within a factor of five with the most recent experimental measurements in both the ferromagnetic and paramagnetic phases. Calculated diffusion coefficients for Mo and W impurities are comparable to or larger than that for Fe self-diffusion at all temperatures below the α-γ phase transition. Calculated activation energies for Ta and Hf impurities suggest that these solutes should also display impurity-diffusion coefficients larger than that for self-diffusion in body-centered cubic Fe.

Original languageEnglish (US)
Pages (from-to)1982-1993
Number of pages12
JournalActa Materialia
Volume58
Issue number6
DOIs
StatePublished - Apr 1 2010

Keywords

  • Ab initio electron theory
  • Bulk diffusion
  • Iron alloys
  • Kinetics

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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