Determining the bilinear flow stress of thin films by comparing load/depth and sink-in/pile-up behavior between nanoindentation and FEM

Abstract It is known from the literature that the load-depth curve obtained by nanoindentation cannot uniquely determine the plastic flow stress behaviour of the material. In this study, the sink-in/pile-up of nanoindentation is another important information for predicting the elastic-plastic behaviour of thin film. Therefore, by comparing load/depth behaviour and sink-in/pile-up from nanoindentation with finite element analysis, the bilinear flow stress of the coating can be determined. Commercial TiN coatings are currently used as an example for this study. The bilinear flow stress of TiN can be determined by this method: the elastic modulus of 343.007 GPa, the yield stress of 10.458 GPa and the tangent modulus of 214.080 GPa. In addition, the stress of loading and unloading during the nanoindentation of the thin film was also investigated.