Adhering layer formation and its effect on the wear of coated carbide tools during turning of a nickel-based alloy

Experiments were carried out to investigate the performance and the wear mechanisms of PVD-TiAlN coated carbide tool in machining of nickel-based alloy GH4169. Adhering layer was formed around the cutting edges under various cutting conditions. The worn surfaces of tool were examined and the elements on the tool surfaces were analyzed by employing scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. The results of SEM micrographs and EDS analyses showed that adherence of workpiece material occurred on both the rake and flank faces under all cutting conditions, and the dominant wear modes of the tool were flank wear, crater on the rake face, and notching at the depth of cut line. The adhering layer protected tool surfaces from the scrubbing action of hard carbide particles, but accelerated the process of the element from tool material diffusing into the workpiece material. In addition, the adhering layer experienced a periodic "formation-stacking-plucking" process at the depth of cut line, leading to the formation of notching. (C) 2011 Elsevier B.V. All rights reserved.