Comparative analysis of the wear behaviour of TiN/TiAlN, TiAlVN, and TiAlYN coated tools in milling operations of Inconel 718

Milling is widely used in the aeronautical and aerospace industries, due to the possibility of producing parts with good dimensional stability and surface quality. Because of its exceptional mechanical qualities and limited thermal conductivity, Inconel 718 is a nickel superalloy that is regarded as a challenging material to process. Due to the flexibility of milling, this is the most commonly used process for machining INCONEL alloys. However, high levels of tool wear can be observed. Coatings can be deposited on the cutting tools to improve process performance. Nonetheless, doping elements such as yttrium and vanadium when added to TiAlN-based coatings can increase the coating's resistance. Furthermore, multilayer coatings tend to be very promising resistance to crack propagation. Thus, this work intends to compare three coatings deposited via PVD, in terms of the quality of the machined surface and wear resulting from the process: TiAlVN, TiAlYN, and TiN/TiAlN. The cutting speed (Vc), feed per tooth (fz), and cutting length (Lcut) were varied. It was possible to verify that the multilayer coating had better results, in terms of average roughness (Ra) and in measuring wear (VB3) and its characterisation. On the other hand, the TiAlVN coating showed the worst results. It was concluded that due to the TiN layer, the TiN/TiAlN coating has better resistance to crack propagation, as its adhesion to the substrate is good and there is no delamination.