Abstract: Thermal oxidation of titanium alloys can improve their overall properties by forming an oxide layer and an oxygen diffusion layer on the surface. Severe plastic deformation of titanium alloys before thermal oxidation can introduce crystal defects such as high density of grain boundaries, dislocations, twin boundaries and high distortion energy, which can promote the absorption of oxygen atom, reduce oxide nucleation temperature, accelerate the growth of oxide film, and promote the diffusion of oxygen atoms into the matrix. Thus, a denser and thicker oxide layer and a deeper oxygen diffusion zone can be formed to obtain better performance. In the study, thermal oxidation of severe plastic deformed titanium alloys is review. Firstly, several common methods of severe plastic deformation are introduced, and the processing conditions and treatment effects of the combined treatment of severe plastic deformation and thermal oxidation of titanium alloys are summarized. Then, according to the general process of oxide formation, the influence mechanism of microstructure changes caused by severe plastic deformation on the absorption of oxygen atom, the nucleation of oxide, the formation of oxide film, the thickening of oxide film and the formation of oxygen diffusion zone is explained. Finally, the effects of severe plastic deformation on thermal oxidation microstructure such as the thickness of oxide film, the range of oxygen diffusion zone and the oxide morphology, as well as the mechanical properties such as hardness, friction and wear, are summarized. The existing problems in the current research are presented, and the future research directions are prospected.

Key words: titanium alloys, severe plastic deformation, thermal oxidation, microstructure, performance