Fast determination of parameters describing manufacturing imperfections and operation wear of nanoindenter tips

Abstract

Nanoindentation is an effective technique for determining mechanical properties of bulk materials and thin films. Prevailing measurement uncertainties in nanoindentations by Vickers or Berkovich diamond pyramids are commonly caused by manufacturing imperfections of the indenter's side angles and tip sharpness. Moreover, the tip geometry changes over the indenter operation time, due to diamond wear.The paper presents a fast method for estimating diamond indenters' tip nano and micro geometry. This method is based on a combination of nanoindentations on Si(100), used as reference material, with FEM supported calculations of Martens hardness. The hardness calculations are conducted using an equivalent indenter tip geometry with geometrical characteristics, which may vary for a specific set of parameters, describing the real indenter with manufacturing imperfections. These parameters are varied in successive iterations until the calculated hardness converges with that of the reference material.For a quick determination of these parameters, the software package “TIDE” (TΙp Deviations Estimation) has been developed. “TIDE” is based on numerous FEM supported simulation results of nanoindentations, conducted on the reference material, varying the indenter tip geometry. By this software package, a quick prediction of nanoindenters' tip equivalent geometry is facilitated, also for anticipating changes due to wear of the diamond over time.