Self-calibration in compliance and indenter tip defect for instrumented indentation

The accuracy in the determination of the mechanical properties by instrumented indentation strongly depends on the indenter/material contact area, the corrective compliance, and the indenter tip defect. For the calibration, we suggest to combine 3 functions: (i) a Force-function, where only the corrective compliance term is the unknown parameter, (ii) an Area-function, allowing the estimation of the tip defect knowing the corrective compliance, and finally (iii) a Martens-function, to determine the Martens hardness. The proposed methodology is validated on a series of experiments performed between 2006 and 2015 on ceramics and metals using the same indentation instrument and the same Vickers indenter having undergone different blunts. As a main result, the Young's moduli are found very close to that available in literature if a n-factor is introduced into the Area-function and Force-function. In addition, both the instrumented hardness and Martens hardness do not vary with the indentation force.

Automated summary

The accuracy of determining mechanical properties in instrumented indentation is influenced by the indenter/material contact area, corrective compliance, and indenter tip defect. This study proposes a calibration method that combines force-function, area-function, and Martens hardness function, and validates it through experiments. The results show that the Young's modulus is close to literature values when introducing an n-factor in the area-function and force-function, and the instrumented hardness and Martens hardness do not vary with indentation force.