Investigation of the effects of GnP-ZrO2 hybrid nanofluids minimum quantity lubrication (NMQL) on the machinability of GH4169

Nickel-based superalloy GH4169 is widely demanded in the aerospace industry due to its superior properties. However, there are some problems such as serious tool wear and poor surface quality in the cutting process of GH4169. In this study, in order to improve the machinability of GH4169, GnP-ZrO2 hybrid nanofluids (NFs) were prepared and applied to cutting machining. Thermophysical properties of the prepared hybrid NFs such as dynamic viscosity, thermal conductivity, and contact angle were tested. Meanwhile, a series of wear tests and turning processes of GH4169 under Dry, MQL, GnPNMQL (GNMQL), GnP-ZrO2 hybrid NMQL (GZNMQL) conditions were conducted to evaluate the performance of NFs. The results showed that the thermophysical property of NFs was improved and the coefficient of friction was significantly reduced with the addition of GnP and ZrO2 hybrid nanoparticles. The machined surface roughness and cutting temperatures under the GZNMQL cooling condition were reduced by 53.53% and 54.06% compared to those under the Dry condition, respectively. Additionally, the tool life was significantly improved. The "flake-spheres-flake" structure of the GnP and ZrO2 improved the lubricity, cooling effect, and friction properties of the cutting fluids, which resulted in a better performance in terms of machined surface roughness, cutting temperatures, and further improved tool life.