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Title: Thermal equation of state of silicon carbide

A large volume press coupled with in-situ energy-dispersive synchrotron X-ray was used to probe the change of silicon carbide (SiC) under high pressure and temperature (P-T) up to 8.1 GPa and 1100 K. The obtained pressure–volume–temperature (P-V-T) data were fitted to a modified high-T Birch-Murnaghan equation of state, yielding values of a series of thermo-elastic parameters, such as, the ambient bulk modulus KTo = 237(2) GPa, temperature derivative of bulk modulus at constant pressure (∂K/∂T)P = -0.037(4) GPa K-1, volumetric thermal expansivity α(0, T)=a+bT with a = 5.77(1)×10-6 K-1 and b = 1.36(2)×10-8 K-2, and pressure derivative of thermal expansion at constant temperature (∂α/∂P)T =6.53±0.64×10-7 K-1GPa-1. Furthermore, we found the temperature derivative of bulk modulus at constant volume, (∂KT/∂T)V, equal to -0.028(4) GPa K-1 by using a thermal pressure approach. In addition, the elastic properties of SiC were determined by density functional theory through the calculation of Helmholtz free energy. Lastly, the computed results generally agree well with the experimental values.
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [3] ;  [4] ;  [4]
  1. Oakland Univ., Rochester, MI (United States)
  2. The Univ. of Toledo, Toledo, OH (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. The Univ. of Nevada, Las Vegas, NV (United States)
Publication Date:
OSTI Identifier:
1332529
Grant/Contract Number:
NA0001982
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 108; Journal Issue: 6; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of Nevada, Las Vegas, NV (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS elastic moduli; carbides; Laser Doppler velocimetry; equations of state; Helmholtz free energy