Improved methods for nanoindentation Berkovich probe calibrations using fused silica

Improved methods are needed to improve the reliability and reporting of Berkovich probe calibrations. Current methods for calibrating machine compliance rely substantially on the subjectivity of the user to choose and exclude from the analysis nanoindentations below a threshold size that are affected by probe tip imperfections or the fused silica surface properties. Furthermore, it can be difficult to identify erroneous experimental data, such as those resulting from dirty or damaged probes. To help overcome these issues in Berkovich probe calibrations, a pre-nanoindentation liftoff analysis and systematic analysis of the Stone-Yoder-Sproul plot were developed. The utility of the analyses was demonstrated through analysis of experimental data. After correcting the fused silica data for machine compliance, the probe area function calibration was performed following established protocols. Finally, a concise protocol for reporting Berkovich probe calibration results was established to improve comparisons between experiments performed with different Berkovich probes.