Finite element analysis on nanoindentation with friction contact at the film/substrate interface

Finite elements (FE) provide a numerical method to calculate complex nanoindentation problems. Correlation of FE analysis with experimental data on nanoindentation may lead to improved characterization of the mechanical properties of thin films and coating systems. In this study, a model of the friction contact at the interface of thin films and substrates is established using FE analysis about a cone indenter, which imitates a Berkovich nanoindenter. Finite element nanoindentation simulations were performed at three different interface friction contact conditions. The following conclusions were depicted through the study of the simulation data. First, for increasing values of the friction coefficient, the indenter's force versus displacement response of the film/substrate-friction-contact (F/SFC) model coincides with the response of the film/substrate-perfectly-bonded (F/SPB) model. Second, when the indenter's maximum displacement is less than 10% of the film thickness the deformed nanoindentation area is concentrated under the indenter tip for both F/SFC and F/SPB models. Third, a mechanical response is generated along the F/SFC interface while the mechanical response along the F/SPB interface is negligible. Finally, the nanoindentation simulation data indicate that the calculated mechanical properties intrinsically depend on the interfacial contact conditions of the film/substrate even when the maximum displacement of the indenter is controlled within the 10% of the thin-film thickness. (c) 2006 Elsevier Ltd. All rights reserved.