Strain Hardening Exponent Base Of Indentation Size Effect (ISE) Of Vickers Hardness

A new approaches to predict the indentation P-h from constitutive material properties has been developed and evaluated for Vickers indentation. This provided a useful tool to evaluate the feasibility of using hardness values in predicting the constitutive material parameters with reference to accuracy and uniqueness by mapping through all potential materials ranges. The extent of ISE can be consistently measured and it can potentially be linked to the H/E ratio. The scale of ISE of the samples tested is fairly repeatable and the link with material properties (e.g H/E) is significant and reliable. This potentially could provide additional set of experimental data reflecting the materials properties. The fundamental reason for ISE is not conclusive, however, a commonly accepted concept (also proved by the link of ISE with H/E) is that it is associated with the gradient strain and dislocation density during the indentation process. Concept to use the indentation size data of the Vickers indentation has been explored to improve the accuracy/robustness of inverse properties modeling based on hardness using steel as material system. The work showed that there is significant ISE in the Vickers hardness tests and the scale and consistency/reliability of ISE was analyzed by fitting data following the power law and proportional resistance model. A new concept of using ISE data for estimating the Strain hardening exponent (n) values of steel has been explored and shown reasonable results for narrowing the range of predicted material properties based on hardness values