Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Poster Session
MM 17.84: Poster
Montag, 26. März 2012, 17:00–19:00, Poster B
Ab initio-based mean field theory of site occupation in binary sigma phases — •Evgeniya Kabliman1, Andrei V. Ruban2, Oleg E. Peil3, Peter Blaha1, Karlheinz Schwarz1, and Börje Johansson2 — 1Institute of Materials Chemistry, Vienna University of Technology, Getreidemarkt 9/165-TC, A-1060 Vienna, Austria — 2Department of Materials Science and Engineering, Applied Material Physics, Royal Institute of Technology, Brinellvägen 23, SE-100 44 Stockholm, Sweden — 3I. Institut of Theoretical Physics, Hamburg University, Jungiusstrasse 9, 20355 Hamburg, Germany
In present work we study the atomic site distribution in binary sigma-phases, which are found in many industrial alloys and usually lead to a destructive effect on the mechanical properties of these alloys. For this purpose we have proposed a simple and powerful approach to calculate the site occupation numbers as function of temperature and composition [1,2]. It is based on the single-site mean-field description of the free energy, where the total energy is expanded in terms of on-site effective cluster interactions, which are calculated as relative chemical potentials. The suggested method has been successfully applied to the Fe-Cr, Co-Cr, Re-W and Fe-V sigma-phases.
[1] E. Kabliman, P. Blaha, K. Schwarz, A. V. Ruban, B. Johansson, Phys. Rev. B 83, 092201 (2011); [2] E. Kabliman, P. Blaha, K. Schwarz, O. Peil, A. V. Ruban, B. Johansson, Phys. Rev. B 84, 184206 (2011).