Contact mechanics of coating-substrate systems. I. Methods of analysis and FEM modelling of nanoindentation tests

摘要

The paper presents method of analysis of indentation test results of coating-substrate systems based on the transformation of indentation curves into stress-strain curves. This method was compared with models provided in literature, and the short review of this models is also given. In part I the indentation tests were analysed using FEM modelling. The effects of substrate properties, film thickness on the deformation of the system and the critical depth of penetration at which the substrate does not affect the measurement results were studied. This was possible by analysis of contact stresses changes with increasing relative penetration depth (RID). It was found that the greatest influence on stresses in the contact area has the ratio of yield strength of coating and substrate Y_c/Y_s. Part II presents the nanoindentation results of ZrN, CrN and a-C:H coatings deposited on different substrates, analysed using the proposed method compared and with FEM results.