General Microhardness Indentation Theory for Multilayer Contacts

Abstract

A refined method for interpreting the Vickers composite microhardness measurement for multilayer materials having layers of arbitrary plating thickness is first presented. The position of an “effective substrate” is found using the concept of the “plastic boundary,” and the depth-wise deformation of each layer is considered in a double-iterative procedure which converges fast. This computational method is then extended from pyramidal indenters to conical and spherical indenters (e.g., Meyer’s). For its confirmation, experimental investigations are carried out for two configurations of Cu/Ni/Au sandwiches, using different diameter spherical indenters and spherical tipped cones, through and well above the microhardness load range. The general rules for composite action are established.