Effects of carbon on Fe-grain-boundary cohesion: First-principles determination

Ruqian Wu, Arthur J Freeman

Research output: Contribution to journalArticle

126 Citations (Scopus)

Abstract

The cohesive properties of the C/FeΣ3(111) grain boundary are investigated by means of the direct determination of the difference in binding energies of C in grain-boundary and free-surface environments. The atomic force approach based on the full-potential linearized augmented plane-wave method is used to optimize the atomic structure for the clean and C-segregated grain-boundary and free-surface systems. The ω phase structure obtained in a previous grain-boundary cluster calculation is found to be only a metastable state that is 0.72 eV/cell (0.81 J/(Formula presented)) higher in energy than the distorted bcc ground state. The calculated binding-energy difference (i.e., Δ(Formula presented)-Δ(Formula presented)) is -0.61 eV/adatom, which is a theoretical demonstration that C is a cohesion enhancer in the Fe grain boundary. Comparisons with earlier results obtained for B, S, and P show that the number of hybridized p electrons and the resulting spatial anisotropy of bonding with the surrounding Fe atoms is the key factor determining the relative embrittling or cohesion enhancing behavior of a metalloid impurity.

Original languageEnglish
Pages (from-to)7504-7509
Number of pages6
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume53
Issue number11
DOIs
Publication statusPublished - Jan 1 1996

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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