DIFFERENTIAL LOAD FEED ANALYSIS - AN ENERGY-RELATED ALTERNATIVE TO THE INTERPRETATION OF HARDNESS INDENTATION MEASUREMENTS

The presented new theoretical approach to the interpretation of hardness indentation measurements is based on an energy-related consideration of the deformation principles in solid state materials under the action of a penetrating indenter. The equations developed therefrom are directly comparable to the first derivative of the experimentally recorded indentation load with respect to the indentation depth. They permit the calculation of specific energies of the different deformation processes. A direct correlation to the conventional hardness conception is derived for the specific energy of isotropic volume densification. The efficiency of the new approach is examined by extensive experimental data of bulk materials as well as coating-substrate composites. The results are shown to demonstrate the correct charge of the energy-related data interpretation. The obtained specific energies permit the quantification of adhesion between substrates and coatings as well as of the extension of specific deformation ranges under the action of the indenter. The results are shown to be in agreement with conventional characterization methods.