Tribology and machinability performance of hybrid Al₂O₃ -MWCNTs nanofluids-assisted MQL for milling Ti-6Al-4 V

Recent burgeoning development in nanotechnology unfolded an avenue in the manufacturing industry. Owing to the superior heat transfer potential of nano-additives, it could be interesting to improve the heat transfer and tribological capability of metal cutting fluids by mixing nanofluids in emulsions properly. To attain high heat transfer performance in cutting difficult-to-cut alloys, hybrid nanofluids-assisted minimum quantity lubrication (MQL) system is applied with the anticipation of efficient lubrication and heat transfer. Taguchi L₁₆(4³) orthogonal array is used involving nanofluids concentrations, air pressure, and cooling flow rate of alumina-multiwalled carbon nanotubes (Al₂O₃-MWCNTs) at constant cutting conditions in the milling of Ti-6Al-4V. The resultant cutting force (F_R), cutting temperature (T), and surface roughness (Ra) are considered key machining responses. Besides, tool wear, chip analysis, and surface topography are also analyzed under the effect of hybrid nanofluids. Findings have shown the minimum resultant force, cutting temperature, and surface roughness of 24.3 N, 148.7 °C, and 0.67 µm, respectively, at nanofluids concentrations of 0.24wt.% and 120 mL/h of flow rate at 0.6 MPa of air pressure. The microscopic analysis of the end-mill depicted minor thermal damage, chip welding, and coating peeling under hybrid nanofluids machining. Also, the chip analysis depicted the clean back chip surface and less melting of saw-tooth chip edges. The surface topography confirmed less chip adhesion and material debris. Results summary showed appropriately chosen MQL parameters improving the cooling/lubrication performance by providing oil film and enhancing the milling performance measures. The outcomes of the proposed study are useful for the manufacturing industry to enhance the process performance.