Characterization of a-C:N/TiAlN coating and investigation of their wear behavior

As a widely used material in aerospace and medical industry, Ti6Al4V titanium alloyis regardedas difficult-to-machine.In this study, a-C:N/TiAlN coating was deposited on carbide cutting toolsasan attempt to increase the machinability of this alloy.Wear behavior and cutting performance of the a-C:N/TiAlN coated carbide toolsin face milling of Ti6Al4V were investigated under dry conditions.The effect of coating on cutting forces, chip formation and surface integrity of the workpiecewith regard to surface finishwas investigated.Mechanical and tribological properties of coated samples were characterized by nanoindentation, scratch test, 3D-profilometer, confocal microscope and pin-on-disk test. SEM was employedin combination with EDS for structural and compositional characterization of worn samples. According to the results, abrasive and adhesive wear are dominant tool failures on the coated tools. Higher wear resistance and~15%longer life time were obtained with a-C:N/TiAlN coated carbide toolsin milling of Ti6Al4V. The coating proved to be effective onchip formation and workpiece surface finish.Due to its superior properties in terms of adhesion, wear resistance, surface finish and chip formation, a-C:N/TiAlN coating is a good candidate for use in face milling of Ti6Al4V alloy.