Nickel-titanium (NiTi) alloys have been outstanding and demandabe materials in several critical applications such as aerospace and biomedical industries, on accounts of their excellent mechanical and physical properties. Their inherent properties include superior strength-to-weight ratios, high mechanical strength, excellent corrosion resistance, and unique biocompatibility. However, NiTi alloys are considered to be difficult-to-machine due to poor thermal conductivity, high specific heat, and high strain hardening, which attributed to rapid tool wear and tool failure, as well as poor machined surface finishes. Given the facts that these alloys are quite unique and not yet well understood, a through analysis of the current state of NiTi machinability characteristics is required. Therefore, this experimental study was initiated to evaluate the performance of titanium aluminium nitride (TiAIN) coated and uncoated carbide drills with respect to tool wear, tool life, tool failure modes, thrust force, surface roughness, surface defects and dimensional accuracy under two different cutting conditions of flood coolants and minimum quantity nanolubricants (MQNL). Cutting speeds of 10, 20 and 30 m/min and constant feed rate of 0.02 mm/rev were employed in the aforementioned cooling and lubricating conditions. The results show that =t TiAIN coated carbide tools under MQNL condition outperformed the uncoated carbide tools under flood condition. It exhibited improvement of 9.68%, 88% and 75.49%, with respect to number drilled holes, tool life and also induced thrust force, respectively. Nonetheless, MQNL was found to produce rougher surface compared to flood conditions which resulted in several surface defects and higher average hole diameter.
