LAUSR

Abstract The diffusion mechanism of interstitial solute elements in α-Ti was investigated using first-principles calculations. Solute elements, B, C, N, O and F, were confirmed to be the most stable at octahedral sites with their calculated formation energies. The migration energies of C, N and O are high, approximately 2 eV, while those of B and F were approximately 1 eV. A high correlation was observed between the migration energies and difference in the charge densities of the solute atoms between stable and transition states. These results indicate that migration energies and resultant diffusion could not be determined only by the atomic radii of solute atoms, and charge transfer must also be taken into consideration. The charge transfer between matrix and solute atoms affects diffusion mechanism of solute atoms in Ti.