Stability, Elastic Constants and Thermodynamic Properties of (α, β, γ)-Nb5Si3 Phases

First principles calculations have been carried out to investigate the structural stability, the elastic constants, the thermodynamic properties and the electronic structure of the intermetallic compounds α-Nb5Si, β-Nb5Si and γ-Nb5Si3. The optimized structural parameters are well consistent with the experimental values. Cohesive energy and formation enthalpy show that α-Nb5Si has the strongest structural stability. The independent single-crystal elastic constants at zero pressure as well as polycrystalline elastic parameters have been calculated by Voigt-Reuss-Hill averaging scheme. The mechanical properties of the different Nb5Si3 phases such as ductility and elastic anisotropy were further analyzed and discussed.