Mechanical properties of vanadium carbide and a ternary vanadium tungsten carbide

• Published in: Solid state communications 2010-04, Vol.150 (15), p.697-700
• Main Authors: Sun, Zhimei, Ahuja, R., Lowther, J.E.
• Format: Article
• Language: English
• Subjects: A. Metals; Condensed matter: structure, mechanical and thermal properties; Cubic lattice; D. Elasticity; D. Electronic band structure; D. Mechanical properties; Elasticity; Elasticity, elastic constants; Electronic band structure; Exact sciences and technology; Fysik; Lattice vacancies; Mathematical analysis; Mechanical and acoustical properties of condensed matter; Mechanical properties; Mechanical properties of solids; Metals; Modulus of elasticity; NATURAL SCIENCES; NATURVETENSKAP; Physics; Stress-strain relationships; Symmetry; TECHNOLOGY; TEKNIKVETENSKAP; Vanadium base alloys; Vanadium carbide
• ISSN: 0038-1098; 1879-2766; 1879-2766
• DOI: 10.1016/j.ssc.2010.01.043

Ab initio total energy calculations are performed on non-stoichiometric vanadium carbide with supercells representing vacancy concentrations of V C 0.875 and V C 0.75. The V C 0.875 supercell retains a cubic symmetry whilst in the case of the V C 0.75 supercell C vacancies located in close proximity have the lowest energy configuration and the cubic lattice slightly distorts to a monoclinic symmetry. Using a stress–strain calculational procedure, the elastic constants of both the cubic and the monoclinic systems are deduced. In all cases C vacancies decrease the elastic moduli. A similar analysis is then applied to consider when W is incorporated into VC. In this case it is found that the elastic moduli increase with W content suggesting that a V-W-C alloy could have significant potential as a novel hard material.