Study on the formation mechanism of oxide film of pure titanium during the cutting process

The industrial pure titanium (TA2) can be oxidized to produce the dense oxide film acted by the effect of thermal-mechanical coupling on the machined surface during the cutting process, which influences its mechanical properties. The characteristics of oxide film were investigated by a single factor cutting test. The phase analysis of the oxide film was carried out. The topography of the oxide film was observed. The formation mechanism of oxide film was studied by the first-principles. The oxide film is uneven, which its roughness increases with the increase of feed rate. The oxide film is mainly composed of TiO2, and the intensity of the TiO2 diffraction peak increases with the increase of feed rate, that is, the amount of TiO2 also increases gradually. When TA2 is oxidized at high temperature, O atoms are adsorbed by Ti atoms to the machined surface to form the corresponding O-Ti covalent bond. The bonding ability between O atoms and Ti atoms is gradually weakened from the machined surface to the inside of the matrix.