Effect of Scratching Speed on Nano-scratched Performance of γ-TiAl Alloy Under Water Lubrication

Abstract:

γ-TiAl alloys feature superior high-temperature performance and low-density properties. However, the inherent brittleness of γ-TiAl alloys poses significant challenges to precision machining. As a highly promising machining approach, water lubrication enables temperature reduction and mitigates frictional heat accumulation, tool wear, and crack-associated defects. This work investigated the effects of nano-scratching speed on scratching force, temperature evolution, plastic deformation, and surface quality of single-crystal γ-TiAl alloy under water lubrication. The results show that the coupling effect between scratching speed and water lubrication governs the machinability and surface quality of single-crystal γ-TiAl alloys. An increase in scratching speed substantially elevates scratching force and frictional heat, which further induces local temperature rise and stress concentration. In comparison, a 1-nm-thick water lubrication layer yields minor temperature fluctuation of the substrate and delivers favorable cooling capacity. At a scratching speed of 400 m/s, water lubrication alleviates surface plastic deformation and damage, promotes chip accumulation, and reduces surface roughness. Experimental observations further confirm that scratching speed exerts a pronounced effect on surface quality.