Cracking During Nanoindentation and its Use in the Measurement of Fracture Toughness

Abstract

Results of an investigation aimed at developing a technique by which the fracture toughness of a thin film or small volume can be determined in nanoindentation experiments are reported. The method is based on the radial cracking which occurs when brittle materials are deformed by a sharp indenter such as a Vickers or Berkovich diamond. In microindentation experiments, the lengths of radial cracks have been found to correlate reasonably well with fracture toughness, and a simple semi-empirical method has been developed to compute the toughness from the crack lengths. However, a problem is encountered in extending this method into the nanoindentation regime with the standard Berkovich indenter in that there are well defined loads, called cracking thresholds, below which indentation cracking does not occur in most brittle materials. We have recently found that the problems imposed by the cracking threshold can be largely overcome by using an indenter with the geometry of the corner of a cube. For the cube-corner indenter, cracking thresholds in most brittle materials are as small as 1 mN (∼ 0.1 grams). In addition, the simple, well-developed relationship between toughness and crack length used for the Vickers indenter in the microindentation regime can be used for the cube-corner indenter in the nanoindentation regime provided a different empirical constant is used.

This is a preview of subscription content, access via your institution.

References

  1. 1.

    G.M. Pharr and W.C. Oliver, MRS Bulletin 17, 28 (1992).

    Article  Google Scholar 

  2. 2.

    W.C. Oliver, MRS Bulletin 11, 15 (1986).

    Article  Google Scholar 

  3. 3.

    M.F. Doerner and W.D. Nix, J. Mater. Res. 1, 601 (1986).

    Article  Google Scholar 

  4. 4.

    W.C. Oliver and G.M. Pharr, J. Mater. Res. 7, 1564 (1992).

    CAS  Article  Google Scholar 

  5. 5.

    M.J. Mayo and W.D. Nix, Acta Metall. 36, 2183 (1988).

    CAS  Article  Google Scholar 

  6. 6.

    B.R. Lawn, A.G. Evans, and D.B. Marshall, J. Am. Ceram. Soc. 63, 574 (1980).

    CAS  Article  Google Scholar 

  7. 7.

    G.R. Anstis, P. Chantikul, B.R. Lawn, and D.B. Marshall, J. Am. Ceram Soc. 64, 533 (1981)

    CAS  Article  Google Scholar 

  8. 8.

    J. Lankford, and D.L. Davidson, J. Mater. Sci. 14, 1662 (1979).

    CAS  Article  Google Scholar 

  9. 9.

    K. Hirao and M. Tomozawa, J. Am. Ceram. Soc. 70, 497 (1987).

    CAS  Article  Google Scholar 

  10. 10.

    A. Arora, D.B. Marshall, B.R. Lawn, and M.V. Swain, J. Non-Cryst. Sol. 31, 415 (1979).

    CAS  Article  Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to D. S. Harding.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Harding, D.S., Oliver, W.C. & Pharr, G.M. Cracking During Nanoindentation and its Use in the Measurement of Fracture Toughness. MRS Online Proceedings Library 356, 663–668 (1994). https://doi.org/10.1557/PROC-356-663

Download citation