First-principles calculations on bcc-hcp transition of titanium

Bcc-hcp transition of titanium was investigated by the first-principles cal culations. Very accurate calculations using the gradient-corrected full-pot ential linear muffin-tin orbital correctly estimated the hcp structure slig htly lower in energy than the omega structure. The adiabatic potential ener gy surfaces of the distortions related to the structural transformations sh owed 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 co ntribution stabilizes the bcc structure over the hcp structure above 3000 K . (C) 2001 Elsevier Science B.V. All rights reserved.