Tribological Property of Titanium Alloy Surface with Different Texture Structure under Dry Friction and Perfluoropolyether Lubrication

Texture structures with varying dimple diameters and densities were produced on titanium alloy surface by laser processing technique. The friction and wear behaviors of the resulting titanium alloy with different texture structures were evaluated by UMT friction and wear tester, and the morphologies of the worn surfaces were characterized by surface profilometer and scanning electron microscopy. The chemical states of typical elements on worn surfaces were examined by means of X - ray photoelectron spectroscopy. The results show that the texture structure and morphology remarkably affected the capacity of holding wear debris and surface contact stress of the as-prepared surface under dry friction. The modified titanium alloy surface with texture morphology of 200 μm dimple diameter and 8.7% dimple density exhibited the best anti-wear and friction-reducing ability among all modified samples. Its friction coefficient and wear rate were reduced by 23.0% and 39.7%, respectively, as compared to the untreated titanium alloy surface, which was mainly due to the accumulation of debris in the dimples and thus reducing wear caused by third-body. As lubricated by PFPE, the surface texture affected the lubrication state and the metal fluoride was formed on the friction surface during rubbing process. The sample with texture morphology of 200 μm dimple diameter and 8.7% dimple density also revealed better friction-reducing and anti-wear properties than the untextured one. Its friction coefficient and wear rate were reduced by 17.4% and 30.6% respectively, which mainly resulted from higher amount of FeF₂ produced on textured surface that can reduce friction and wear during the rubbing process.