First-principles calculations on bcc–hcp transition of titanium

Bcc–hcp transition of titanium was investigated by the first-principles calculations. Very accurate calculations using the gradient-corrected full-potential linear muffin-tin orbital correctly estimated the hcp structure slightly lower in energy than the ω structure. The adiabatic potential energy surfaces of the distortions related to the structural transformations showed similar with those of Zr. The curvatures of the potential surfaces at the equilibrium bcc point are very small and negative, which suggests that Ti has strong anisotropic characters of bondings. The electronic thermal contribution stabilizes the bcc structure over the hcp structure above 3000 K.