Calibration issues for nanoindentation experiments: direct atomic force microscopy measurements and indirect methods.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Accurate measurement of the diamond area function (DAF) is critical for shallow depth nanoindentation experiments.
• Existing calibration methods may introduce inaccuracies, particularly at shallow depths.
• Berkovich tips are commonly used in nanoindentation, necessitating reliable calibration.

Purpose of the Study:

• To address calibration issues in shallow depth nanoindentation with Berkovich tips.
• To compare the accuracy of direct DAF measurement via AFM with a novel indirect calibration method.
• To evaluate the sensitivity and convergence of indirect calibration procedures.

Main Methods:

• Direct measurement of the DAF using atomic force microscopy (AFM) imaging of the Berkovich tip at shallow depths.
• A novel indirect calibration method utilizing an iterative scheme to simultaneously determine reduced modulus and indentation hardness.
• Indentation measurements on fused silica across a 0.5-200 mN load range using a Berkovich indenter.

Main Results:

• Comparison of direct AFM-based DAF measurement with the novel indirect calibration method.
• Evaluation of the novel indirect method's performance against standard indirect calibration procedures.
• Sensitivity and convergence studies performed for both indirect calibration approaches.

Conclusions:

• The study provides a comparative analysis of different calibration strategies for nanoindentation.
• The novel indirect method offers a robust alternative for accurate DAF determination.
• Findings contribute to improving the reliability of mechanical property measurements at the nanoscale.