▎ 摘　　要

In this study, turning of titanium (Ti-6Al-4V) alloy under four different environments as dry, vegetable oil under minimum quantity lubrication (MQL), texture on the rake face filled with graphene particles, and graphene-mixed vegetable oil under nanoparticle-based minimum quantity lubrication (NMQL) with textured carbide tools is investigated. Results shows that maximum tool life, lower cutting forces, and minimum cutting temperature generated are with NMQL followed by MQL, texture filled with graphene, and dry turning. The tool life under NMQL is improved by 178 to 190%, main cutting force minimized by 36 to 40%, and cutting temperature reduced by 31 to 42% as compared with dry condition at various cutting speeds. The best turning performance is achieved under NMQL which is mainly due to higher thermal conductivity of MQL fluid mixture and shearing action imparted by graphene on different contact surfaces of tool. Further, the phenomena of improved thermal conductivity and shearing action imparted by graphene are explained by using transient hot-wire/SEM/Raman spectroscopy in this study. Finally, it is concluded that graphene has potential to act as lubricant/coolant in turning processes.