Metrological Comparison of Available Methods to Correct Edge-Effect Local Plasticity in Instrumented Indentation Test

Area of Science:

• Materials Science
• Mechanical Engineering
• Metrology

Background:

• Instrumented Indentation Test (IIT) is crucial for material characterization across scales.
• Material plasticity at indentation edges introduces significant biases in IIT results.
• Existing correction methods lack comprehensive metrological performance comparisons.

Purpose of the Study:

• To introduce a metrological framework for comparing IIT plasticity correction methods.
• To evaluate the accuracy and uncertainty of various correction techniques.
• To identify the most suitable methods for different applications.

Main Methods:

• Literature review of existing IIT plasticity correction methods.
• Development and application of a metrological comparison framework.
• Evaluation of work-based, topographical, Nix-Gao, and electrical contact resistance (ECR) approaches.
• Comparison using calibrated reference materials for traceability.

Main Results:

• The Nix-Gao model demonstrated the highest accuracy (0.28 GPa) with an expanded uncertainty of 0.57 GPa.
• The ECR approach exhibited the highest precision (0.33 GPa accuracy, 0.37 GPa expanded uncertainty).
• ECR enables practical in-line and real-time material characterization.

Conclusions:

• A novel metrological framework facilitates objective comparison of IIT correction methods.
• The Nix-Gao model is recommended for high-accuracy material characterization.
• ECR is the preferred method for applications requiring real-time, in-line analysis and high precision.