Self-adaptive wear behavior of nano-multilayered TiAlCrN/WN coatings under severe machining conditions

Application of quaternary nitride (Ti,Cr,Al) N/WN nano-multilayered coatings results in a significant increase of tool life as well as wear behavior improvement under conditions of dry high-speed machining (end milling) of hardened H13 steel (HRC 50). Investigations of surface structure characteristics of TiAlCrN/WN coatings using TEM, SEM, EDX, and XPS have been performed. The microhardness, modulus of elasticity, coefficient of friction and the oxidation stability of the coatings were also studied. Cutting forces at the tool/workpiece interface have been measured in situ. It was shown that the major cause of the cutting tool life and wear behavior improvement is the enhanced tribological adaptability of a TiAlCrN/WN coating. By means of adding W to the composition of TiAlCrN/WN nano-multilayered coatings, W–O tribo-films form in synergy to alumina and provide tool life improvement.