| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1600117 | Intermetallics | 2014 | 8 Pages |
•The temperature-dependent mechanical properties of α-/β-Nb5Si3 phases are studied.•A new approach is introduced to optimize the temperature-dependent lattice constants.•Both of α-Nb5Si3 phase and β-Nb5Si3 phase show obvious crystal anisotropy.•Effect of temperature on the mechanical properties of α-/β-Nb5Si3 phases is analyzed.
The temperature-dependent structural properties and anisotropic thermal expansion coefficients of α-/β-Nb5Si3 phases have been determined by minimizing the non-equilibrium Gibbs free energy as functions of crystallographic deformations. The results indicate that the crystal anisotropy of α-Nb5Si3 phase is much more temperature dependence than that of β-Nb5Si3 phase. The total/partial density of states of α-/β-Nb5Si3 phases are discussed in detail to analyze their electronic hybridizations. It is demonstrated that the bonding of the two phases is mainly contributed from the hybridization between Nb-4d and Si-3p electronic states. The temperature-dependent mechanical properties of α-/β-Nb5Si3 phases are further investigated via the quasi-harmonic approximation method in coupling with continuum elasticity theory. The calculated single-crystalline and polycrystalline elasticity shows that both phases are mechanically stable and exhibit the intrinsic brittleness. The results also suggest that α-Nb5Si3 phase possesses a superior ability of compression resistance but an inferior ability of high-temperature resistance of mechanical properties than those of β-Nb5Si3 phase. The bonding features of α-/β-Nb5Si3 phases are discussed by means of charge density difference analysis in order to explain the difference of the temperature-dependent mechanical properties between the two phases.
