EFFECT OF ION-IMPLANTATION ON THE RESIDUAL-STRESS, TRIBOLOGICAL AND MACHINING BEHAVIOR OF CVD AND PVD TIN-COATED CEMENTED CARBIDE CUTTING-TOOL INSERTS

The ion implantation of cemented carbide cutting tool inserts often re sults in increased tool life. In the present work, contributing mechan isms were clarified by taking commercial cutting tool inserts, coated with TiN by conventional chemical and physical vapor deposition (CVD a nd PVD), and implanting them with either nitrogen ions or the dual nic kel-titanium metal ions. The residual stress, microhardness and specif ic wear rate profiles were measured and the inserts were tested in the turning of stainless steel or a titanium alloy. The results show that changes in the lifetime of these TiN coated tools are not due to a ch ange in the residual stress but to changes in the microhardness profil e and tribological properties through the coatings after ion implantat ion. It is also hypothesized that the dual metal ion implant reduces t he coefficient of friction during the turning operation.