Influence of oxygen content on the mechanical properties of hexagonal Ti-First principles calculations

In this work we report results of ab initio modeling of structure stability, mechanical properties, lattice distortion and electronic structures of α-Ti as a function of concentration and positions of oxygen atoms. The heats of formation for all solutions were negative and in excellent agreement with experimental data. The single crystal elastic constants, elastic modulus anisotropy and polycrystalline Voigt bulk B and shear G moduli were calculated. Based on the values of B/G ratio, the effect of oxygen on Ti ductility was estimated with the conclusion that approximately 1 at% O addition improves elastic and plastic properties. This can be explained by the effect of O concentration on the Ti-Ti bonds and the value of the c/a lattice parameter.