Wear Behavior Analysis of TiN/TiAlN Coated Tools in Milling of Inconel 718

Inconel 718, widely used in the production of parts for the aeronautical and aerospace industries is considered a difficult-to-machine alloy due to its high hardness, tendency to harden by cold work, and low thermal conductivity at high temperatures. Among the machining processes, milling is the most used owing to its simplicity, flexible and ability to generates parts with a high surface-quality finishing. Coated tools have been used to successfully improve the milling performance of Ni alloys. Thus, the wear behavior of endmill coated tools were evaluated, as well as the influence of machining parameters, such as cutting speed and cutting length, in the milling of Inconel 718, using multi-layered TiN/TiAlN coating, deposited by a novel sputtering deposition technique, HiPIMS – high power impulse magnetron sputtering process. For this, the roughness of the machined surface, the wear of the tool and the wear mechanisms presented were analyzed. It was verified that increasing the parameters, the surface roughness and flank wear also increased. The predominant wear mechanisms observed were abrasion and material adhesion. Furthermore, it was observed that the presence of the multilayer coating enabled greater resistance to the formation of cracks due to the presence of the TiN layer. There is a gap in the literature regarding the milling and finishing operations of Inconel 718. As this alloy has low machinability, the study of machining process optimization is of great industrial interest. The conclusions of this work can serve as a basis for the optimization of the machining process of this alloy.