Simulation of Berkovich nanoindentation experiments on thin films using finite element method (vol 312, pg 240, 1998)

The Finite element technique is applied for studying the very complex stres s-strain field of thin hard coatings subjected to a nanoindentation process . Berkovich indentation experiments were simulated with the ABAQUS finite e lement software package. The investigated system was titanium nitride on hi gh speed steel as an example of a hard film on a softer substrate. The nume rical analysis allowed the plastic deformation history during indentation t o be followed. In particular, it was possible to correlate the onset of pla stic deformation in the substrate with the shape of the loading curve. The system was simulated by an axisymmetric model in which the conical indenter has the same contact area as the Berkovich indenter. A six-fold symmetric three-dimensional model was also defined for testing the suitability of the previous model. The indenter was modeled either as a rigid surface or as a deformable diamond tip. Comparison between the experimental data and numer ical results demonstrated that the finite element approach is capable of re producing the loading-unloading behavior of a nanoindentation test. The fil m hardness of TiN/HSS specimens was numerically calculated for different in dentation depths. It was shown that the presence of the substrate affected the hardness measurement for relative indentation depths greater than about 15% of the film thickness. (C) 1998 Published by Elsevier Science S.A. All rights reserved.