The Evaluation of Tribological Performance of Laser Micro-Texturing Ti6Al4V Under Lubrication With Protic Ionic Liquid

Laser micro-texturing treatment has been proved as an efficient way to improve tribological properties of metal alloys. Meanwhile, ionic liquids also show great potential as novel lubricant additives to increase the durability of contacting components and decrease the energy loss during tribological process. This study investigated the influence of the laser micro texturing surfaces on the tribological performance of titanium alloy Ti6Al4V under different lubricant conditions. In this research, two sets of dimple-textured surfaces created by different laser parameters, energy density and area density, were fabricated on Ti6Al4V. Polyalphaolefin (PAO) 40 and 1 wt.% 2-hydroxyethylammonium 2-ethylhexanoate (Eet) used as additive to PAO 40 were designed as lubricants during the sliding tests. First, the geometrical properties of laser micro-textures on the surfaces were characterized. The wetting behaviors of different lubricants on textured surfaces were then examined based on contact angle measurement. All the frictional tests were carried out on the ball-on-flat reciprocating tribometer under the same working conditions. Lastly, the surface morphology of the wear tracks on Ti6Al4V and tungsten carbide balls and their wear mechanisms were evaluated by using the optical microscope, scanning electron microscope, and energy-dispersive X-ray spectroscopy. The results exhibit the laser micro-textures have a positive effect on improving the tribological performance of Ti6Al4V. Meanwhile, the use of Eet as the lubricant additive to PAO 40 can facilitate the formation of the tribo-layer, which enhances the tribological behavior of laser micro-texturing Ti6Al4V surfaces.