Thin hard coatings stress-strain curve determination through a FEM supported evaluation of nanoindentation test results

The widespread use of thin hard physical vapor deposited (PVD) coatings in various technical applications necessitates the precise knowledge of their mechanical properties. Up to now the coating elasticity and plasticity properties were approached with the aid of simplified considerations of the nanoindentation procedure and a consequent evaluation of the obtained nanohardness measurement results, depending, however, on the indentation load. In the present paper a continuous finite elements method (FEM) simulation of the nanoindentation hardness test is introduced in order to describe the coating elastic and plastic deformation during this test and herewith to extract precisely and independent of the indentation load the coating stress-strain curve. Characteristic applications of the developed procedure demonstrate the adequacy of this method to determine the coatings constitutive laws of various coating materials deposited under different conditions. (C) 2001 Elsevier Science BN. All rights reserved.