| Title |
Mechanical Behavior : Assessment of Elastic Modulus and Hardness for (100) Tungsten Single Crystal through Elastic Analysis of Nano-Indentation Curve and Pile-Up Prediction |
| Authors |
이윤희(Yun Hee Lee); 권동일(Dong Il Kwon) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Nano-indentation; Hardness; Elastic modulus; Hertzian contact; File-up behavior |
| 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. |