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First principles calculations of vacancy–vacancy interactions in nickel: thermal expansion effects

Megchiche, El Hocine and Mijoule, Claude and Amarouche, Mohand First principles calculations of vacancy–vacancy interactions in nickel: thermal expansion effects. (2010) Journal of Physics : Condensed Matter, vol. 22 (n° 48). ISSN 0953-8984

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Official URL: http://dx.doi.org/10.1088/0953-8984/22/48/485502

Abstract

The energetic properties of the divacancy defect in fcc nickel are studied by ab initio calculations based on density functional theory. The formation and binding enthalpies of the divacancy in the first (1nn), second (2nn) and third (3nn) nearest-neighbor configurations are presented. Results show that the 1nn divacancy configuration is the most stable with a formation enthalpy H2vf of 2.71 eV and a small binding energy H2vb of 0.03 eV. In the 2nn configuration, the monovacancy–monovacancy interaction is repulsive, and it vanishes in the 3nn configuration. The migration process of the divacancy in its stable configuration is studied. We find that the divacancy migrates in the (111) plane by successive rotational steps of 60°. The corresponding migration enthalpy H2vm is predicted to be 0.59 eV, about half of that found for the monovacancy. For a better comparison of our results with high temperature experimental data, we have analyzed the effects of thermal expansion. Our results show that the inclusion of thermal expansion allows us to reproduce satisfactorily the experimental predictions.

Item Type:Article
Additional Information:Thanks to Institute of Physics editor. The definitive version is available at http://iopscience.iop.org/ The original PDF of the article can be found at Journal of Physics : Condensed Matter website : http://iopscience.iop.org/0953-8984/22/48/485502
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT
Université de Toulouse > Université Paul Sabatier-Toulouse III - UPS
Other partners > Université Mouloud Mammeri Tizi Ouzou - UMMTO (ALGERIA)
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Deposited By:Leila Abdelouhab

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