Synergistic effects of graphite and molybdenum disulfide solid lubricants embedded in femtosecond laser-textured polycrystalline cubic boron nitride tools on cutting performance of Ti-6Al-4V

Abstract

To address the inherent challenges in machining Ti-6Al-4V—namely severe tool wear, poor surface roughness, and unfavorable chip morphology (e.g. chip curling)—this paper proposes an experimental approach utilizing micro-dimple textures filled with a hybrid of graphite and molybdenum disulfide (MoS₂) solid lubricants. The micro-dimple textures were fabricated on the rake face of polycrystalline cubic boron nitride tools via femtosecond laser texturing, followed by embedding graphite, MoS₂, and their hybrid mixtures into the textures to develop self-lubricating tools. Dry cutting experiments were conducted to comprehensively evaluate the machining performance based on rake face wear morphology, surface roughness, microhardness, chip morphology, and chip serration degree. The results demonstrate that, compared to the conventional tool (T0), the hybrid-lubricated tool (T4) significantly mitigates tool wear. Specifically, Ti-element adhesion was reduced by approximately 18%, while surface roughness, microhardness, and the chip serration degree were decreased by about 26%, 18%, and 19%, respectively.