Thermal expansion coefficient of WRe alloys from first principles

Thomas Dengg, Vsevolod Razumovskiy, Lorenz Romaner, Georg Kresse, Peter Puschnig, and Jürgen Spitaler
Phys. Rev. B 96, 035148 – Published 26 July 2017

Abstract

We calculate the coefficient of thermal expansion (CTE) in tungsten-rhenium random alloys for Re concentrations between 0% and 50% and for temperatures up to 2400 K by employing the quasiharmonic approximation within the ab initio framework of density functional theory. We treat chemical disorder by the virtual crystal approximation and compute the phonon density of states at two levels of sophistication. While the traditional Debye-Grüneisen (DG) model fails to account for the experimentally observed increase in CTE upon Re addition for concentrations above 10% Re, explicit phonon calculations within density functional perturbation theory lead to an overall good agreement with experiment. Thereby we identify the pronounced phonon softening and anisotropy between transversal and longitudinal modes in W-Re to be responsible for the breakdown of the DG model.

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  • Received 20 December 2016
  • Revised 18 April 2017

DOI:https://doi.org/10.1103/PhysRevB.96.035148

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Thomas Dengg1,2, Vsevolod Razumovskiy1, Lorenz Romaner1, Georg Kresse3, Peter Puschnig2, and Jürgen Spitaler1

  • 1Materials Center Leoben Forschung GmbH, Roseggerstraße 12, 8700 Leoben, Austria
  • 2University of Graz, Institute of Physics, NAWI Graz, Universitätsplatz 5, 8010 Graz, Austria
  • 3Institut für Materialphysik and Center for Computational Materials Science, Universität Wien, 1090 Wien, Austria

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Issue

Vol. 96, Iss. 3 — 15 July 2017

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