The Tensile Properties, Scratch Behaviors and Sliding Wear of Oxide Scale Formed on Titanium Grade 2.

The tensile properties, scratch behaviors and sliding wear of an oxide scale obtained on the surface of titanium Grade 2 in the process of isothermal oxidation at 600, 700 and 800 °C were determined in the study. It was shown that the intensity of the oxidation process increased along with an increase in temperature and extension of the oxidation time, which translated directly into the thickness of the deposited oxide layers. The tests showed that isothermal oxidation had an adverse effect on the tensile properties of titanium. After oxidation, it was found that the maximum reduction in tensile strength, R _m , was approximately 17.5%, and of the yield point, R _p0.2 , approximately 13.9%. Examination of scratch behaviors of the oxide scale showed that the layers obtained at temperatures of 700 (72 h) and 800 °C (2 and 6 h) had the best adhesion properties. The best resistance to scratching was exhibited by the layer obtained after 6 h oxidation at 800 °C (critical load: L _c1 = 63 N, L _c2 = 85 N). The study showed that after oxidation, a considerable reduction in wear factor of a disc made of titanium Grade 2 was observed for both the friction couples used (Al ₂ O ₃ , steel 100Cr6). The maximum reduction in wear factor of the oxidized titanium disc during interaction with Al ₂ O ₃ balls was ca. 79%, and with 100Cr6 balls, ca. 96%.