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First‐principles investigations on elevated temperature elastic and thermodynamic properties of ZrB 2 and HfB 2
Author(s) -
Xiang Huimin,
Feng Zhihai,
Li Zhongping,
Zhou Yanchun
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14877
Subject(s) - anisotropy , materials science , thermal expansion , phonon , thermal conductivity , thermodynamics , work (physics) , thermal , lattice (music) , condensed matter physics , dispersion (optics) , grüneisen parameter , composite material , physics , acoustics , optics , quantum mechanics
As promising candidates for ultrahigh temperature applications, high‐temperature properties, which are quite rare and fragmentary, have great significance to ZrB 2 and HfB 2 . In this work, thermodynamic and mechanical properties of ZrB 2 and HfB 2 from 0 K to 2000 K were investigated by a combination of first principles calculations and quasi‐harmonic approximations. The ground‐state properties, including lattice parameters, elastic constants, phonon dispersion, and mode‐Grüneisen parameters are calculated. The theoretical thermal expansion, elastic and thermodynamic properties at elevated temperatures show good agreement with experiments. By discussing Grüneisen parameters anisotropy, the mechanism for the thermal expansion anisotropy of ZrB 2 and HfB 2 is uncovered. The influence of direction‐dependent sound velocities on the anisotropy of thermal conductivity is also discussed.