Investigation on methods for dealing with pile-up errors in evaluating the mechanical properties of thin metal films at sub-micron scale on hard substrates by nanoindentation technique

Two quantitative approaches are proposed in this paper in order to deal with the significant errors produced during evaluating the mechanical properties of soft metal films on hard substrates by using nanoindention technique, which depend on calculating actual contact area (CACA: area) and correcting contact depth errors (CCDE: depth). The hardness and elastic modulus of films-only for two elastically matching systems with film thickness of about 500 run, Au/glass-ceramic and Al/7059 glass, are then obtained by using the methods. The above parameters are also determined by the Oliver and Pharr method and the constant modulus assumption analysis (CMAA: modulus) for comparisons. In CMAA: modulus, the values are assumed to be independent of the contact area and contact depth. The results indicate that the two methods are both able to correct severe pile-up errors in the Oliver and Pharr analysis and produce a relative high accuracy. (C) 2008 Elsevier B.V. All rights reserved.