| Abstract |
| Hardness and elastic modulus calculated from the Oliver and Pharr`s indentation curve analysis are overestimated for ductile metals comparing with the values measured from the direct observation of residual indentation impression. A dominant cause of the phenomenon is material pile-up around contact. However it is very difficult to consider the pile-up in analyzing the indentation curve without observing the residual indentation mark. Therefore, we propose an indirect analysis of the pile-up effect by estimating the elastic modulus independently based on the Hertzian contact theory. Pile-up corrected contact area is predicted from the conventional elastic recovery equation by inserting the pre-determined elastic modulus. The proposed analysis is applied to the nano-indentation tests on (100) tungsten single crystal and produced a reasonable hardness comparing with the direct observation result through an atomic force microscope. |
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| Key Words |
| Nano-indentation, Hardness, Elastic modulus, Hertzian contact, File-up behavior |
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