Coupled effects of vortex tube hybrid cooling with minimal quantity reinforced nanoparticle lubricants in turning NiTi alloys

Phase transformation of nickel-titanium (NiTi) alloys due to temperature rise during machining process can deliberately deliver poor machinability. Hence, this study investigated the hybrid cooling and lubricating effects of nano-minimum quantity lubricant (NanoMQL) with vortex chilled air of NiTi machining. NanoMQL with vortex chilled air depicted a consistently low tool wear of 0.14 mm as compared to other conditions despite experiencing similar cutting duration, particularly for a lower speed of 12.5 m/min. Likewise, the hybrid cooling method had a profound effect towards tool wear resistant when cutting speed was doubled. A reduced cutting force of 108–185 N and a 15–18% improvement on surface roughness was also observed under the hybrid coolant and lubrication. Conclusively, a substantial improvement towards machinability of NiTi alloys was evidenced in this study.