Determination of plastic properties of surface modification layer of metallic materials from scratch tests

A new test method was proposed to extract plastic parameters, i.e., yield stress and strain hardening index, and interfacial coefficient of friction of metallic materials via scratch tests with a pyramid indenter based on dimensional analysis and finite element analysis. Yield stress and strain hardening index of scratched materials can be calculated with scratch width, residual scratch depth and normal force obtained from the scratch tests. Interfacial coefficient of friction between the scratched materials and scratch tip can be determined by the ratio of tangential force and normal force. The accuracies of the proposed formulas were verified by comparing the results of uncarburized and carburized 18CrNiMo7-6 alloy steel obtained by conventional methods with those by scratch tests. This work provides a convenient method to determine plastic parameters and interfacial coefficient of friction of metallic materials simultaneously, which is important for the mechanical analysis, design and safety evaluation of mechanical parts.

Automated summary

A new test method based on dimensional analysis and finite element analysis was proposed to extract plastic parameters and interfacial coefficient of friction of metallic materials via scratch tests. The proposed formulas were proven to be accurate through comparison with conventional methods.