Structural, Elastic, Mechanical and Electronic Properties of NbW-Based Intermetallic Compounds: First-Principles Calculations

The structural, elastic and electronic properties of NbW-based intermetallic compounds have been investigated by first-principles calculations from CASTEP code based on density functional theory (DFT). The calculated lattice parameters of NbW-based intermetallic compounds are in good agreement with the experimental values. The calculated elastic constants indicate that NbW, CNb0.8W0.2, Mo0.333Nb0.333W0.333, Nb0.33Ta0.33W0.34, Nb0.75Se2W0.25, and Nb2.25S6W0.75 have mechanically stable structures. The bulk modulus, shear modulus, Young's modulus, and Poisson's ratio are obtained. With the addition of Ta element, the ductility of NbW-based alloys increases obviously. With the addition of non-metallic elements, it can be decreased. Among the six compounds, Nb0.33Ta0.33W0.34 has the best plasticity and the stiffness of CNb0.8W0.2 is the highest. The results show that NbW, Mo0.333Nb0.333W0.333, Nb0.33Ta0.33W0.34, and Nb2.25S6W0.75 are ductile, and CNb0.8W0.2 as well as Nb0.75Se2W0.25 are brittle. Furthermore, all NbW-based intermetallic compounds considered in this work are conductors.