Investigation of the performance of cermet tools in the turning of Haynes 25 superalloy under gaseous N2 and hybrid nanofluid cutting environments

Abstract

Co-based superalloys such as Ni-based, Fe-based, and other such superalloys are classified as difficult-to-machine materials. Due to the poor machinability of superalloys, their machining is a big challenge for metal cutting industries. However, the machining of superalloys under ecological cutting environments (e.g., MQL, nanofluids, cryogenic cooling, etc.) has shown promising results. The present study investigated the effects of ecological cutting environments on the performance of cermet cutting tools. To this purpose, Co-based Haynes 25 superalloy was turned under MQL, graphene nanoplatelet (GnP) doped mono nanofluids, multiwalled carbon nanotube (MWCNT) doped mono nanofluids, GnP/MWCNT doped hybrid nanofluids, gaseous N2 based cutting environments, and mono/hybrid nanofluids combined with N2. Viscosity, pH, thermal conductivity, and wettability properties were investigated to determine the characteristics of the nanofluid mixtures. Cutting temperature, tool wear, wear mechanisms, surface roughness, surface topography, and chip formation morphology were chosen as the machining performance criteria. The experimental results showed that the cermet cutting tool and the GnP/MWCNT+N2 hybrid cutting environment contributed significantly to the Haynes 25 machining performance. Compared to the dry cutting environment, the N2 cutting environment showed the best performance improvement (63.57%) for cutting temperature, whereas the GnP/MWCNT+N2 hybrid cutting environment yielded the best performance and the best the improvement in tool flank wear (45.13%) and surface roughness (36.36%).