Mechanisms of oxidation anisotropy between α-Ti (0001) and 011¯0 crystallographic planes in titanium matrix composites

Abstract To reveal oxidation mechanisms of different crystallographic planes for further improving the oxidation resistance of titanium alloys, short-term oxidation tests and first-principle calculations were combined for investigating the oxidation anisotropy of Ti in titanium matrix composites. The results showed that the thickness of oxides formed on Ti(0001) surface was thinner than that on the other surfaces including Ti 01 1 ¯ 0 surface, exhibiting a better oxidation resistance. The calculation results of adsorption energies and diffusion barriers of oxygen atoms on Ti(0001) and Ti 01 1 ¯ 0 surfaces have revealed the microcosmic mechanism. Ti(0001) surface with higher adsorption energy and diffusion barrier than those of Ti 01 1 ¯ 0 surface can efficiently hinder the dissolution of oxygen in Ti and subsequent formation of oxides on the surface.