Evaluation of Mechanical and Surface Integrities in Cemented Carbides Processed by Femtosecond Laser Machining and PVD-Coating

Lasers are widely applied in modern industries, ranging from subtractive machining to additive manufacturing. Pulsed laser technology has significantly advanced precision machining, particularly for hard or refractory materials that are challenging to process using conventional methods. Cemented carbides exemplify such materials, serving as essential components in cutting tools and wear-resistant parts. In practice, these carbides are frequently coated to enhance wear resistance and extend service life. Previous studies show that nanosecond lasers could improve the performance of coated cemented carbides but induced microscale thermal side effects. Femtosecond lasers can minimize these effects, reducing issues like melting and pore formation. This study examines the surface and mechanical integrity of femtosecond-laser-machined cemented carbides with subsequent PVD coating. Vickers hardness, micro-scratch testing, and post-scratch topographical analysis were applied to evaluate coating performance and surface integrity. Results show that femtosecond laser processing minimally alters surface integrity, causing only slight changes in roughness, morphology, and microstructure. It enhances hardness and scratch resistance compared to untreated samples. In particular, low-energy processing, especially with perpendicular sliding across laser-induced features, further boosts coating performance.