Thermal expansion coefficient of WRe alloys from first principles

Autor(en)

Thomas Dengg, Vsevolod Razumovskiy, Lorenz Romaner, Georg Kresse, Peter Puschnig, Juergen Spitaler

Abstrakt

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.

Organisation(en)

Computergestützte Materialphysik

Externe Organisation(en)

Materials Center Leoben, Forschung GmbH, Karl-Franzens-Universität Graz

Journal

Physical Review B

Band

96

Anzahl der Seiten

10

ISSN

2469-9950

DOI

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

Publikationsdatum

07-2017

Peer-reviewed

Ja

ÖFOS 2012

103025 Quantenmechanik, 103036 Theoretische Physik, 103015 Kondensierte Materie, 103009 Festkörperphysik

Schlagwörter

ASJC Scopus Sachgebiete

Electronic, Optical and Magnetic Materials, Condensed Matter Physics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/ad89c236-a36f-4698-983c-ef73e5410be1