LAUSR

Abstract Nanofluids in minimum quantity lubrication (MQL) machining is gaining grounds with environment consciousness enhanced laws and regulations consummated. Researchers have worked upon several aspects related to the characteristics and applications of nanofluids in MQL machining. The present work is an effort to review some of these works and to understand the effect of the size, shape, type, concentration, and thermal conductivity of nanoparticles, and the type and thermal conductivity of the base fluid on process performance. The review shows that the thermophysical, tribological, and wetting characteristics of nanofluids and the MQL parameters affect the process performance. Further, the MQL machining performance has been reported as significantly varying by the augmentation of nanofluids by a unique kind of nanoparticles and/or mixed with different types of nanoparticles (hybrid nanofluid). Nanofluids, namely graphene oxide and paraffin-based and soybean-based mixed with MoS2 nanoparticles and hybrid nanofluids, namely alumina-multiwalled carbon nanotubes and alumina-graphene reported as imparting superior lubrication and cooling effects under MQL machining. However, thermophysical and wetting characteristics of hybrid nanofluids with aging and issues related to clustering of nanoparticles at higher concentrations need to be researched for the utmost advantage of their usage in machining processes. The present work finally lists down certain areas that can be taken up for further research in the hybridization of nanofluids and their long-term stability to get a synergistic effect on the MQL machining performance.