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The Role of Indentation Depth on the Measured Hardness of Materials

Published online by Cambridge University Press:  15 February 2011

Melissa Shell De Guzman ,
Gabi Neubauer ,
Paul Flinn  and
William D. Nix
Melissa Shell De Guzman
Affiliation:
Intel Corporation, P.O. Box 58119, MS: SC2-24, 2200 Mission College Blvd., Santa Clara, CA 95052-8119
Gabi Neubauer
Affiliation:
Intel Corporation, P.O. Box 58119, MS: SC2-24, 2200 Mission College Blvd., Santa Clara, CA 95052-8119
Paul Flinn
Affiliation:
Intel Corporation, P.O. Box 58119, MS: SC2-24, 2200 Mission College Blvd., Santa Clara, CA 95052-8119
William D. Nix
Affiliation:
Stanford University, Department of Materials Science and Engineering, Bldg 550, Peterson Lab, Stanford CA 94305-2205
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Abstract

Ultra micro-indentation tests on Ni and Cu samples showed increasing hardness with decreasing penetration depth over a range from 200 to 2000 nm. The results suggest increased strain hardening with decreased indentation depth. To establish that this is a real material effect, a series of tests were conducted on amorphous materials, for which strain hardening is not expected. The hardness of Metglas® was found to be independent of depth. A simple model of the dislocation densities produced under the indenter tip describes the data well. The model is based on the fact that the high density of dislocations expected under a shallow indentation would cause an increase in measured hardness. At large depths, the density of geometrically necessary dislocations is sufficiently small to have little effect on hardness, and the measured hardness approaches the intrinsic hardness of the material.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 308: Symposium M1 – Thin Films: Stresses and Mechanical Properties IV , 1993 , 613
Copyright
Copyright © Materials Research Society 1993

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References

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