Femtosecond Laser Micro-Texturing of Surfaces for Enhanced Friction Reduction Performance
Laser surface texturing has emerged as a key technology for reducing frictional losses in lubricated sliding systems. Surface textures have been used and found to be beneficial in literature to enhance the properties of the surface by decreasing friction. However, no systematic approach has yet been established to design and optimize micro-texture geometries for enhanced hydrodynamic pressure build-up and friction reduction. In this work, an ultrashort-pulsed femtosecond laser was used in order to accurately engrave surface textures at the micro-scale while avoiding thermal damage. The femtosecond laser parameters were optimized in order to achieve micro-textures with sharply defined features and geometries. Computational Fluid Dynamics (CFD) simulations were employed to analyze hydrodynamic pressure generation, flow behavior and lubricant pathways within the micro-texture and lubricant film. The simulation results guided the design optimization process, resulting in a novel micro-texture. A custom tribo-device was manufactured for surface-to-surface contact in order to experimentally validate the simulated trends. The novel micro-texture, which features a smooth and gradual convergence from a large inlet area to a narrower outlet area, was found to enhance the wedge effect over a longer distance, increasing the hydrodynamic pressure build-up compared to the untextured case. Experimentally, the novel micro-texture reduced frictional losses by 17.76% relative to the untextured case and outperformed conventional micro-textures. In order to enhance further the friction performance, the novel micro-texture was combined with graphene and MoS₂ solid lubricant additives. A synergetic friction reduction of 29.69% was achieved, attributed to texture-induced film thickening, particle retention within the texture, particle transport through the lubricant film, leading to the formation of low-shear tribofilms at the contact interface. These findings provide a basis for effective micro-texture design in sliding components in the automotive and aerospace industries.
Project Details
- Student(s): Marc Chamoun
- Advisor(s): Dr. Roland Bejjani
- Year: 2025-2026