Hostname: page-component-f554764f5-fr72s Total loading time: 0 Render date: 2025-04-09T22:32:12.369Z Has data issue: false hasContentIssue false
  • English
  • Français

Strain gradient plasticity effect in indentation hardness of polymers

Published online by Cambridge University Press:  31 January 2011

Arthur C. M. Chong  and
David C. C. Lam
Arthur C. M. Chong
Affiliation:
Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
David C. C. Lam
Affiliation:
Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
Get access

Abstract

Plasticity in material is typically described as a function of strain, but recent observations from torsion and indentation experiments in metals suggested that plasticity is also dependent on strain gradient. The effects of strain gradient on plastic deformation in thermosetting epoxy and polycarbonate thermoplastic were experimentally investigated by nanoindentation and atomic force microscopy in this study. Both thermosetting and thermoplastic polymers exhibited hardening as a result of imposed strain gradients. Strain gradient plasticity theory developed on the basis of a molecular kinking mechanism has predicted strain gradient hardening in polymers. Comparisons made between indentation data and theoretical predictions correlated well. This suggests that strain gradient plasticity in glassy polymers is determined by molecular kinking mechanisms.

Type
Articles
Information
Journal of Materials Research , Volume 14 , Issue 10 , October 1999 , pp. 4103 - 4110
Copyright
Copyright © Materials Research Society 1999

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.)

Article purchase

Temporarily unavailable

References

REFERENCES

1.Ma, Q. and Clarke, D.R., J. Mater. Res. 10, 853 (1994).CrossRefGoogle Scholar
2.Fleck, N.A., Muller, G.M., Ashby, M.F., and Hutchinson, J.W., Acta Metall. Mater. 42, 475 (1994).CrossRefGoogle Scholar
3.Nix, W.D. and Gao, H., J. Mech. Phys. Solids 46, 411 (1998).CrossRefGoogle Scholar
4.Lam, D.C.C and Chong, A.C.M, J. Mater. Res. 14, 3784 (1999).CrossRefGoogle Scholar
5.Doerner, M.F. and Nix, W.D., J. Mater. Res. 1, 601 (1986).CrossRefGoogle Scholar
6.Oliver, W.C. and Pharr, G.M., J. Mater. Res. 7, 1564 (1992).CrossRefGoogle Scholar
7.Sneddon, I.N., Int. J. Eng. Sci. 3, 47 (1965).CrossRefGoogle Scholar
8.Prime, R.B., Thermal Characterization of Polymeric Materials (Academic Press, San Diego, CA, 1997), pp. 1379–1765.Google Scholar
9.Chanda, M. and Roy, S.K., Plastics Technology Handbook (M. Dekker, New York, 1993), pp. 369–570.Google Scholar
10.Skoog, D.A., Holler, F.J., and Nieman, T.A., Principles of Instrumental Analysis (Saunders College: Harcourt Brace College, Philadelphia, PA, 1998), pp. 535–562.Google Scholar
11.Ashby, M.F. and Jones, D.R.H, Engineering Materials 1: An Introduction to Their Properties and Applications (Pergamon Press, New York, 1993), pp. 71–85.Google Scholar
12.Lam, D.C.C and Chong, A.C.M (unpublished).Google Scholar