Wear behavior of adaptive nano-multilayered TiAlCrN/NbN coatings under dry high performance machining conditions

Application of quaternary nitride nano-multilayered coatings results in significant improvements in tool life as well as wear behavior of ball nose end mills under severe conditions of dry high speed machining of hardened H13 steel (HRC 55-57). Tool life of different nano-multilayered TiAlCrN-based coatings with addition of transitional metals based (of V and VI groups) nitride layers has been compared. Tool life of TiAlCrN/NbN coating was found to be higher than compared to the other nano-multilayered coatings. Investigation of surface structure characteristics of the TiAlCrN/NbN coating using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and High Resolution Electron Energy Loss Spectroscopy (HREELS) has been performed. The properties of the coatings such as microhardness, modulus of elasticity, coefficient of friction and oxidation stability at elevated temperatures were also studied. Cutting forces at the tool/workpiece interface have been measured in-situ. Temperatures on the surface of cutting tools were evaluated. The features of friction and wear behavior as well as mechanisms of tribo-adaptation of TiAlCrN/NbN nano-multilayered coatings were outlined.