Experimental evaluation of the lubrication performances of different nanofluids for minimum quantity lubrication (MQL) in milling Ti-6Al-4V

The objective of this research is to experimentally evaluate the lubrication performances of different nanofluids in milling titanium alloy Ti-6Al-4V. Six types of nanofluids, namely, Al2O3, SiO2, MoS2, CNTs, SiC, and graphite, were selected. Cottonseed oil was used as the base oil. The lubrication performance was investigated in terms of milling force, surface roughness, and morphology of workpiece surface. Experimental results demonstrated that the Al2O3 nanoparticle obtained the minimal milling force (F-x=277.5N, F-y=88.3N), followed by the SiO2 nanoparticle (F-x=283.6N, F-y=86.5N). The surface roughness obtained by the Al2O3 nanofluid was the minimum (R-a=0.594m), whereas it was the maximum by using minimum quantity lubrication (R-a=1.772m). The surface roughness of the six nanofluids was described by the following order: Al2O3<SiO2<MoS2<CNTs<graphite<SiC. The workpiece surface morphology was the best for Al2O3 and SiO2. The viscosity of the nanofluids was also analyzed. Spherical Al2O3 and SiO2 nanoparticles improved the lubrication effect of base oil mostly and were more suitable as environment-friendly additives for the base oil compared with the others.