Theoretical investigation of the elastic, Vickers hardness and thermodynamic properties of δ-WN under pressure

• Published in: Materials science in semiconductor processing 2014-11, Vol.27, p.883-890
• Main Authors: Wei, Jin Cheng, Chen, Hai Chuan, Huang, Wen, Long, Jianping
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Debye temperature; Elastic properties; Elasticity. Plasticity; Exact sciences and technology; Hardness; Mechanical and acoustical properties of condensed matter; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Mechanical properties of solids; Melting point; Metals. Metallurgy; Minimum thermal conductivity; Physics; Thermal properties of condensed matter; Thermal properties of crystalline solids; Thermodynamic properties; Tribology and hardness; Vickers hardness
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2014.08.041

The crystal structural, elastic and thermodynamic properties of δ-WN under pressure are investigated by using the first-principles. The ground states properties are found to agree with the available experimental data and other theoretical results. The elastic constants, shear modulus and Young׳s modulus under pressure are calculated; the results show that the δ-WN is mechanically stable, which is consistent with the experiments data by Wang [Wang et al., Chem. Mater. 24 (2012) 3023] and the theoretical results by Yu [Yu et al., J. Alloys Compd. 487 (2009) 556]. The ductility of δ-WN was analyzed using the B/G ratio and Poisson׳s ratio σ. Finally, thermodynamic properties have been predicted, the results show that the Debye temperature, melting point and the minimum thermal conductivity increases when the pressure is increased, while specific heat coefficient γ decreases with increasing pressure.