Core structure of a screw dislocation in Ti from density functional theory and classical potentials

M. Ghazisaeidi, D. R. Trinkle

Research output: Contribution to journalArticlepeer-review

Abstract

Previous density functional theory (DFT) studies of the 1/3 〈12̄10〉 screw dislocation in titanium have shown metastable core structures depending on the initial position of the dislocation line. We investigate this problem by modeling a screw dislocation with two initial positions using both DFT and a modified embedded atom (MEAM) potential for Ti with flexible boundary conditions. Both DFT and MEAM produce initial-position-dependent core structures. The MEAM potential stacking fault energies and core structures are in good agreement with DFT. MEAM potential computes the core energies and shows the behavior of both cores under applied strain. We found that the higher-energy core always reconstructs into the lower-energy one independent of the applied strain direction. Transformation from low- to high-energy core was not observed. Therefore, at T = 0 K, only the low-energy core is stable under applied strain.

Original languageEnglish (US)
Pages (from-to)1287-1292
Number of pages6
JournalActa Materialia
Volume60
Issue number3
DOIs
StatePublished - Feb 2012

Keywords

  • Core structure
  • Density functional theory
  • Dislocations
  • Plastic deformation
  • Titanium

ASJC Scopus subject areas

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

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