Elastic and plastic work of indentation as a characteristic of wear behavior for cutting tools with nitride PVD coatings

The chemical and phase composition as well as the structural characteristics of TiN-based PVD versus the nitrogen pressure used during deposition coatings were analyzed using AES and XRD methods. Also the friction and wear properties of the coatings were established under different wear conditions. Using these results a relation between the TiN PVD coating's wear resistance and its ability to dissipate the energy of plastic deformation as well as to accumulate the energy of elastic deformation were obtained by using a nano-indentation method. Based on this work a microhardness dissipation parameter (MDP) was developed to serve as an indicator of a coating's durability. MDP is a ratio of the energy of dissipation to the total energy associated with elastic-plastic deformation measured during nanoindentation. An optimal range of MDP for TiN PVD coating was suggested for different wear modes experienced by cutting and stamping tools. The connection between MDP and the hardness-elastic modulus (H/E) ratio was also considered.