Properties of TiN–Al2O3–TiCN–TiN, TiAlN, and DLC‐coated Ti(C,N)‐based cermets and their wear behaviors during dry cutting of 7075 aluminum alloys

Abstract In the work, TiAlN for physical vapor deposition (PVD), multilayer TiN‐Al 2 O 3 ‐TiCN‐TiN for chemical vapor deposition (CVD), and diamond‐like carbon (DLC) for plasma‐enhanced chemical vapor deposition (PECVD) were deposited on the cermet inserts. Characteristics and wear behaviors of the three coated cermets during dry cutting of 7075 aluminum alloys were observed. The results show that TiN‐Al 2 O 3 ‐TiCN‐TiN coatings have highest adhesion strength and hardness. At the cutting speed of 1100 r/min, the depth of 0.2 mm, and the feed rate of 0.1 mm/r, the three coated inserts show the best wear‐resistant properties. In this case, TiN/Al 2 O 3 /TiCN/TiN shows the worst wear‐resistant properties (value of the flank wear [VBB] = 0.062 mm), while DLC coatings show the most excellent wear‐resistant properties (VBB = 0.046 mm). During the cutting of aluminum alloys, which have high plasticity and low melting point, adhesive wear dominate on the flank of the inserts. The thickest coating of TiN/Al 2 O 3 /TiCN/TiN results in the bluntest cutting edge, which form the most serious adhesive worn zone. For the TiAlN and DLC coatings, due to a smaller cutting force, the two coatings have much better wear resistance. Further, the self‐lubricating properties of DLC show excellent effect on protecting the inserts. Thus, the DLC‐coated cermets have the best wear‐resistant properties. Further, the TiAlN‐coated cermets have the widest wear‐affected zone while the DLC coating has the narrowest.