A Knoop-Indentation Method for R-Curve Determination



The stable growth of indentation cracks during a bending test offers an interesting possibility to study the R-curve behaviour of ceramics. The suitability of Knoop crack for such crack growth experiments is investigated on a silicon nitride.

For a proper evaluation of crack growth data the dependence of the geometric correction factor Y and of the residual stress parameter χ on crack length and indentation load have to be taken into account. Methods are developed to determine Y and χ and their change with indentation load and crack length. The measurement of R-curves is possible if Y — and χ — values determined by these methods are used for the evaluation of crack growth data.

For the investigated material a slightly rising R-curve was determined. Because of the low crack length to indent diagonal ratio of Knoop cracks a lower limit of c = 120 μm was introduced to the experimental range covered with Knoop cracks in this material.


Nickel Zirconia Brittle Nitride Pyramid 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    J.B. Wachtman, Mechanical Properties of Ceramics, John Wiley & Sons Inc., New York (1996).Google Scholar
  2. 2.
    B.R. Lawn, Fracture Of Brittle Solids, Cambridge University Press, Cambridge (1993).CrossRefGoogle Scholar
  3. 3.
    P. Chantikul, G.R. Anstis, B.R. Lawn, D.B. Marshall, A critical evaluation of indentation techniques for measuring fracture toughness: II, strength method, J. Am. Ceram. Soc., 64, 539 - 543 (1981).CrossRefGoogle Scholar
  4. 4.
    R.F. Krause, Rising fracture toughness from bending strength of indented alumina bars, J. Am. Ceram. Soc., 71, 338 - 343 (1988).CrossRefGoogle Scholar
  5. 5.
    L.M. Braun, S.J. Bennison, B.R. Lawn, Objective evaluation of short-crack toughness curves using indentation flaws: case study on alumina-based ceramics, J. Am. Ceram. Soc., 75, 3049 - 3057 (1992).CrossRefGoogle Scholar
  6. 6.
    V.M. Sgalvo, P. Pancheri, Crack decorating technique for fracture-toughness measurement in Alumina, J. Eur. Ceram. Soc., 17, 1697 - 1706 (1997).CrossRefGoogle Scholar
  7. 7.
    V.M. Sglavo, R. Dal Maschio, Controlled indentation-induced cracks for the determination of fracture toughness in alumina, Fracture Mechanics of Ceramics, 11, 233 - 243 (1996).Google Scholar
  8. 8.
    G.R. Anstis, P. Chantikul, B.R. Lawn, D.B. Marshall, A critical evaluation of indentation techniques for measuring fracture toughness: I, direct crack measurements, J Am. Ceram. Soc., 64, 533 - 538 (1981).CrossRefGoogle Scholar
  9. 9.
    B.R. Lawn, A.G. Evans, D.B. Marshall, Elastic/plastic indentation damage in ceramics: the median/radial crack system, J. Am. Ceram. Soc., 63, 574 - 581 (1980).CrossRefGoogle Scholar
  10. 10.
    D.K. Shetty, A.R. Rosenfield, W. Duckworth, Analysis of indentation crack as a wedge-loaded half-penny crack, J. Am. Ceram. Soc., 68, C65 - C67 (1985).CrossRefGoogle Scholar
  11. 11.
    M.S. Kaliszewski, G. Behrens, A.H. Heuer et al., Indentation studies on Y203-stabilized ZrO2: I, development of indentation-induced cracks, J. Am. Ceram. Soc., 77, 1185 - 1193 (1994).CrossRefGoogle Scholar
  12. 12.
    G.W. Dransmann, R.W. Steinbrech, A. Pajares et al., Indentation studies on Y203-stabilized ZrO2: I, toughness determination from stable growth of indentation-induced Cracks, J Am. Ceram. Soc., 77, 1194 - 1201 (1994).CrossRefGoogle Scholar
  13. 13.
    R.F. Cook, L.M. Braun, W.R. Cannon, Trapped cracks at indentations, part I: experiments on yttria-tetragonal zirconia polycrystals, J. Mat. Sci., 29, 2133 - 2142 (1994).CrossRefGoogle Scholar
  14. 14.
    A.M. El Aslabi, G. Kleist, R.W. Steinbrech, H. Nickel, Evaluation of indentation fracture toughness of Si3N4 using crack profile measurements, Fortschrittsberichte der DKG, 6, 133 - 149 (1991).Google Scholar
  15. 15.
    S.L. Jones, C.J.Norman, R. Shahani, Crack-profile shapes formed under a Vickers indent pyramid, J. Mat. Sci. Let., 6, 721 - 723 (1987).CrossRefGoogle Scholar
  16. 16.
    R.J. Damani, C. Schuster, R. Danzer, Polished notch modification of SENB-S fracture toughness testing, J. Eur. Ceram. Soc., 17, 1685 - 1689 (1997).CrossRefGoogle Scholar
  17. 17.
    J. Kiibler, Fracture toughness of ceramics using the SENVB method: first results of a joint VAMAS/ESIS round robin, Ceram. Eng. Sci. Proc.,to be published.Google Scholar
  18. 18.
    P. Pancheri, P. Bosetti, R. Dal Maschio, V.M. Sglavo, Production of sharp cracks in ceramic materials by three-point bending of sandwiched specimens, Eng. Fracs. Mech., 59, 447 - 456 (1998).CrossRefGoogle Scholar
  19. 19.
    S.S. Chiang, D.B. Marshall, A.G. Evans, The response of solids to elastic/plastic indentation: I, stresses and residual stresses, J. Appl. Phys., 53, 298 - 311 (1982).CrossRefGoogle Scholar
  20. 20.
    J.C. Newman, I.S. Raju, An empirical stress-intensity factor equation for the surface crack, Eng. Fract. Mech., 15, 185 - 192 (1981).CrossRefGoogle Scholar
  21. 21.
    R.F. Krause, Flat and rising R-curves for elliptical surface cracks from indentation and superimposed flexure, J Amer. Ceram. Soc., 77, 172 - 187 (1994).CrossRefGoogle Scholar
  22. 22.
    D. Bleise, R.W. Steinbrech, Flat R-curve from stable propagation of indentation cracks in coarse-grained alumina, J Am. Ceram. Soc., 77, 315 - 322 (1994).CrossRefGoogle Scholar
  23. 23.
    D.B. Marshall, Controlled flaws in ceramics: a comparison of Knoop and Vickers indentations, J. Am. Ceram. Soc., 66, 127 - 131 (1983).CrossRefGoogle Scholar
  24. 24.
    L.M. Keer, T.N. Farris, J.-C. Lee, Knoop and Vickers indentation in ceramics analysed as a three-dimensional fracture, J. Am. Ceram. Soc., 69, 392 - 396 (1986).CrossRefGoogle Scholar
  25. 25.
    R.F. Cook, B.R. Lawn, A modified indentation toughness technique, J. Amer. Ceram. Soc., 66, C200 - C210 (1983).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2002

Authors and Affiliations

  • T. Lube
    • 1
  1. 1.Department of Structural and Functional CeramicsUniversity of LeobenLeobenAustria

Personalised recommendations