Ab initio investigation of the Nb-Al system

Elastic and thermodynamic properties for the stable phases in the Nb-Al system were studied with the first-principles pseudo-potential plane-wave method based on density functional theory. The temperature dependence of the enthalpy of formation for the NbAl3 and Nb2Al intermetallics are reported for the first time using the quasi-harmonic approximation. The elastic properties of Nb2Al and the linear thermal expansion coefficient and the elastic properties versus temperature of the Nb3Al are reported for the first time. The calculations would suggest that the NbAl3 is the stiffest and most brittle of the Nb-Al intermetallics.