Electronic mechanism of impurity-dislocation interactions in intermetallics: NiAl

O. Yu Kontsevoi, Yu N. Gornostyrev, Arthur J Freeman, M. I. Katsnelson, A. V. Trefilov

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Abstract

The nature of impurity-dislocation interactions is one of the key questions governing the strength and plasticity of solid-solution materials. To investigate the influence of impurities on the mechanical properties of intermetallic NiAl, the electronic structure and energy of NiAl with a 〈100〉{010} edge dislocation and transition-metal impurities was calculated using the real-space tight-binding linear muffin-tin orbital method. The localized electronic states, appearing in the core of the dislocation, are found to lead to strong impurity-dislocation interactions via two mechanisms: firstly, chemical locking, due to strong hybridization between impurity electronic states and dislocation localized states; secondly, electrostatic locking, due to long-range charge oscillations caused by the electron localization in the dislocation core. The results obtained explain qualitatively why the solid-solution hardening effect in NiAl correlates with the electronic structure of impurities rather than with size misfit, as expected according to traditional views.

Original languageEnglish
Pages (from-to)455-463
Number of pages9
JournalPhilosophical Magazine Letters
Volume81
Issue number7
DOIs
Publication statusPublished - Jul 2001

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ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

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