Thermophysical Properties of α-Tungsten Carbide

• Published in: Journal of the American Ceramic Society 1999-01, Vol.82 (1), p.129-135
• Main Authors: Reeber, Robert R., Wang, Kai
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Heat capacities of solids; Physics; Thermal expansion; thermomechanical effects and density; Thermal properties of condensed matter; Thermal properties of crystalline solids
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.1999.tb01732.x

Upper and lower bounds for the thermal expansion of polycrystalline tungsten carbide (α‐WC) are predicted at ultrahigh temperatures from low‐temperature experimental data. The lower bound is obtained from an αVKTV model, where αV is the volume thermal expansion, KT the isothermal bulk modulus for a randomly oriented polycrystalline sample, and V the molar volume. For many materials, the αVKTV product approaches a constant value that is similar to the specific heat at the highest temperatures. The upper bound uses Grüneisen's rule with a constant Grüneisen parameter gamma at temperatures >1.3θD (where θD is the Debye temperature) and experimental data below that temperature. Literature data for the thermophysical properties of α‐WC have been reviewed and used in our αVKTV model to calculate a lower bound for the thermal expansion at temperatures >2θD and to calculate the temperature dependence of the bulk modulus. The ultrahigh‐pressure thermal expansion has been calculated from the lower bound. Model predictions of the thermophysical properties of WC are given for an extended temperature range.