Sustainable machining of heat resistant superalloys using hybrid nanofluid based minimum quantity lubrication

Improving the machinability of nickel-based superalloys remains a significant challenge in modern manufacturing, particularly for aerospace and high-performance engineering applications. Excessive friction and elevated temperatures during machining often result in rapid tool wear and reduced efficiency. This study investigates the potential of eco-friendly hybrid nanofluids-engineered by combining nanoparticles with complementary thermal and lubricating characteristics-as a sustainable solution to enhance machining performance. Specifically, the performance of three hybrid nanofluid combinations-hexagonal boron nitride/graphite (hBN/Gr), hBN/molybdenum disulfide (MoS₂), and Gr/MoS₂-was evaluated during the milling of Inconel 601 under varied cutting speeds (30-60 m/min) and feed rates (0.05-0.15 mm/rev). Key machining responses such as cutting force, surface roughness, tool wear, temperature, and tool life were analyzed. Among the tested combinations, the hBN/Gr nanofluid demonstrated superior performance, achieving reductions in cutting force (4.17%), surface roughness (21.05%), cutting temperature (8.57%), and tool wear (19.25%), along with an 11.17% improvement in tool life compared to Gr/MoS₂. These enhancements are attributed to the fluid's optimal viscosity and exceptional tribological behavior at the tool-chip interface. The study offers a novel, environmentally responsible approach to machining Inconel 601, emphasizing the promising role of hybrid nanofluids-particularly hBN/Gr-as next-generation lubricants in sustainable manufacturing.