Load-dependence of the measured hardness of Ti(C,N)-based cermets

The Vickers hardnesses of a series of Ti(C,N)-based cermets were measured in the indentation load range from 1.47 to 40.67 N. It was found that the examined materials exhibit a reversed indentation size effect, i.e. the measured hardness increases with increasing indentation load. Both Meyerʹs law and the energy balance model can not provide a proper description for the observed experimental phenomena, while the polynomial series representation can describe the experimental data very well. A possible explanation for the cause of the observed reverse indentation size effect was also proposed.