Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-27T02:20:03.205Z Has data issue: false hasContentIssue false
  • English
  • Français

Nanoindentation of Soft Films On Hard Substrates: Experiments And Finite Element Simulations

Published online by Cambridge University Press:  10 February 2011

G. M. Pharr ,
A. Bolshakov ,
T. Y. Tsui  and
Jack C. Hay
G. M. Pharr
Affiliation:
Department of Materials Science, Rice University, 6100 Main St., Houston, TX 77005-1892
A. Bolshakov
Affiliation:
Baker Hughes Inteq, P.O. Box 670968, Houston, TX 77267–0968
T. Y. Tsui
Affiliation:
Department of Materials Science, Rice University, 6100 Main St., Houston, TX 77005-1892
Jack C. Hay
Affiliation:
Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
Get access

Abstract

Experiments and finite element simulations have been performed to examine errors in the measurement of hardness and elastic modulus caused by pile-up when soft films deposited on hard substrates are tested by nanoindentation methods. Pile-up is exacerbated in soft-film/hardsubstrate systems by the constraint imposed on plastic deformation in the film by the relatively non-deformable substrate. To experimentally examine pile-up effects, soft aluminum films with thicknesses of240, 650, and 1700 nm were deposited on hard soda-lime glass substrates and tested by nanoindentation techniques. This system is attractive because the elastic modulus of the film and the substrate are approximately the same, but the substrate is harder than the film by a factor of about ten. Consequently, substrate influences on the indentation load-displacement behavior are manifested primarily by differences in the plastic flow characteristics alone. The elastic modulus of the film/substrate system, as measured by nanoindentation techniques, exhibits an increase with indenter penetration depth which peaks at a value approximately 30% greater than the true film modulus at a penetration depth close to the film thickness. Finite element simulation shows that this unusual behavior is caused by substrate-induced enhancement of pile-up. Finite element simulation also shows that the amount of pile-up increases with increasing penetration depth, and that the pile-up geometry depends on the work-hardening characteristics of the film. Because of these effects, nanoindentation techniques overestimate the true film hardness and elastic modulus by as much as 68% and 35%, respectively, depending on the work-hardening behavior of the film and the indenter penetration depth. The largest errors occur in non-work-hardening materials at penetration depths close to the film thickness, for which substrate-induced enhancement of pile-up is greatest.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 505 , 1997 , 109
Copyright
Copyright © Materials Research Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Pharr, G.M. and Oliver, W.C., MRS Bulletin 17, 28 (1992).Google Scholar
2.Oliver, W.C. and Pharr, G.M., J. Mater. Res. 7, 1564 (1992).Google Scholar
3.Doerner, M.F. and Nix, W.D., J. Mater. Res 1, 601 (1986).Google Scholar
4.Loubet, J.L., Georges, J.M., Marchesini, O., and Meille, G., J. Tribology 106, 43 ( 1984).Google Scholar
5.Pethica, J.B., Hutchings, R., and Oliver, W.C., Philos. Mag. A 48, 593 (1983).Google Scholar
6.Tsui, T.Y., Oliver, W.C., and Pharr, G.M., Mater. Res. Soc. Symp. Proc. 436, 207 (1997).Google Scholar
7.Oliver, W.C., McHargue, C.J., and Zinkle, S.J., Thin Solid Films 153, 185 (1987).Google Scholar
8.Oliver, W.C. and McHargue, C.J., Thin Solid Films 161, 117 (1988).Google Scholar
9.Doerner, M.F., Gardner, D.S., and Nix, W.D., J. Mater. Res. 1, 845 (1987).Google Scholar
10.LaFontaine, W.R., Yost, B., and Li, C.-Y., J. Mater. Res. 5, 776 (1990).Google Scholar
11.Stone, D., LaFontaine, W.R., Alexopoulos, P., Wu, T.W., and Li, C.-Y., J. Mater. Res 3, 141 (1988).Google Scholar
12.Stone, D.S., J. Electronic Packing 112, 41–46 (1990).Google Scholar
13.Burnett, P.J. and Rickerby, D.S., Thin Solid Films 148, 41–50 (1987).Google Scholar
14.Burnett, P.J. and Rickerby, D.S., Thin Solid Films 148, 51–65 (1987).Google Scholar
15.Bhattacharya, A.K. and Nix, W.D., Int. J. Solids Structures 24, 1287 (1988).Google Scholar
16.Tsui, T.Y., Ross, C.A., and Pharr, G.M., Mater. Res. Soc. Symp. Proc., in press.Google Scholar
17.Tsui, T.Y., Ross, C.A., and Pharr, G.M., Mater. Res. Soc. Symp. Proc., in press.Google Scholar
18.Tsui, T.Y., Oliver, W.C., and Pharr, G.M., J. Mater. Res. 11, (1996).Google Scholar
19.Bolshakov, A., Oliver, W.C., and Pharr, G.M., J. Mater. Res. 11, (1996).Google Scholar
20.Bolshakov, A., Oliver, W.C., and Pharr, G.M., Mater. Res. Soc. Symp. Proc. 436, 141 (1997).Google Scholar
21.Bolshakov, A. and Pharr, G.M., J. Mater. Res., submitted.Google Scholar
22.Sneddon, I.N., Int. J. Engng. Sci. 3, 47 (1965).Google Scholar
23.Tsui, T.Y., Ph.D. Dissertation, Rice University, 1996.Google Scholar
24.Tsui, T.Y. and Pharr, G.M., J. Mater. Res., submitted.Google Scholar
25.Johnson, K.L., Contact Mechanics (Cambridge University Press, Cambridge, 1985).Google Scholar