Nanoindentation of soft films on hard substrates: The importance of pile-up
- Rice Univ., Houston, TX (United States). Dept. of Materials Science
- Nanoinstruments Inc., Oak Ridge, TN (United States)
Nanoindentation is used for measuring mechanical properties of thin films. This paper addresses potential measurement errors caused by pile-up when soft films deposited on hard substrates are tested this way. Pile-up is exacerbated in soft film/hard substrate systems because of the constraint the substrate exerts on plastic deformation of the film. To examine pile-up effects, Al films 240 and 1700 nm thick were deposited on hard glass and tested by standard nanoindentation. In Al/glass, the film and substrate have similar elastic moduli; thus, any unusual behavior in nanoindentation results may be attributed to differences in plastic flow alone. SEM examination of nanoindentation hardness impressions in the film revealed that common methods for analyzing nanoindentation data underestimate the true contact areas by as much as 80%, which results in overestimations of the hardness and modulus by as much as 80 and 35%, respectively. Sources of these errors and their effect on measurement of hardness and elastic modulus are discussed, and a simple model for the composite hardness of the film/substrate system is developed. This model could prove useful when it is not possible to make indentations shallow enough to avoid substrate effects.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Oak Ridge Associated Universities, Inc., TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464; AC05-76OR00033
- OSTI ID:
- 224850
- Report Number(s):
- CONF-960401-19; ON: DE96009401
- Resource Relation:
- Conference: Spring meeting of the Materials Research Society (MRS), San Francisco, CA (United States), 8-12 Apr 1996; Other Information: PBD: [1996]
- Country of Publication:
- United States
- Language:
- English
Similar Records
Substrate effects on nanoindentation mechanical property measurement of soft films on hard substrates
Finite element studies of the influence of pile-up on the analysis of nanoindentation data