Effects of Femtosecond Laser-Generated Tesla Valve Micro-textures on the Tribological Performance of YG8N Surfaces

Due to its exceptional high-temperature resistance, wear resistance, and hardness, YG8N cemented carbide tools are widely used in various machining applications. During cutting processes, significant friction between the tool and workpiece can lead to tool wear and compromise machining quality. To reduce frictional resistance during cutting, minimize tool wear, and enhance component machining quality, this study investigated the frictional performance of micro-textures on YG8N tool surfaces. Continuous Tesla valve micro-textures were fabricated on the YG8N surface using femtosecond laser technology, with optimal laser parameters identified to achieve the best surface morphology. Hardness tests were conducted on both the original surface and the laser-processed surface. Under oil-lubricated conditions, ball-on-disk friction tests were conducted at 10, 20 and 30 N loads in different directions. A comparative analysis of wear morphology and friction coefficients under different loads and friction directions was conducted, revealing differences in the anisotropic friction performance of the Tesla valve micro-textures.

To reduce the frictional resistance generated during the cutting process of YG8N hard carbide tools and minimize tool wear, the frictional properties of YG8N surfaces with micro-texturing were investigated. Tesla valve micro-textures were fabricated on the YG8N surface using femtosecond laser processing, and ball-on-disk friction tests were conducted under different loads in oil-lubricated conditions. The textured surface achieved the best morphology when processed with a laser power of 40 W and a scanning speed of 100 mm/s. A comparative analysis of the frictional wear morphology and friction coefficients in different sliding directions was performed to study the anisotropic friction behavior of the Tesla valve micro-texture. The experiments showed that at a low lubricant flow speed of 1 m/s, Tesla valve microtextured samples exhibited higher maximum flow speed in the reverse direction than in the forward direction. Under a 10 N load, the reverse direction had the lowest average friction coefficient at 0.102, with a wear rate of 15.5×10⁻² μm²/N, a 62.5% reduction compared to non-textured surfaces. At a higher flow speed of 6 m/s, the forward direction showed higher maximum flow speed than the reverse, with the lowest average friction coefficient of 0.110 at a 20 N load and a wear rate of 9.8×10⁻² μm²/N, a 64.1% reduction relative to non-textured surfaces. These results indicated that at lower lubricant flow speeds, the reverse oil film exhibited greater load-bearing capacity and better hydrodynamic lubrication. As the lubricant flow speed increased, the forward oil film surpassed the reverse in load-bearing capacity, showing improved lubrication and wear-reducing performance. Mechanical mixing occurring during the friction process could enhance the lubrication of the friction surface to some extent, forming a more stable protective layer and improving anti-friction performance. Ultimately, experiments consistently showed that both forward and reverse Tesla valve micro-textures produced lower friction and wear than the non-textured surface, suggesting that the application of such textures could significantly extend tool life, improve machining quality.