Skip to main content
Log in

Nanomechanical properties of nacre

  • Article
  • Published:
Journal of Materials Research Aims and scope Submit manuscript

Abstract

Nacre, the inner iridescent layer of seashells is a model biomimetic system composed of 95% of inorganic (aragonite) phase and 5% of organic phase. Nacre exhibits an interlocked layered “brick and mortar” structure where the bricks are made up of aragonitic calcium carbonate and mortar is an organic phase. Here, we report the role of indentation load and penetration depth on measurement of nanomechanical properties of nacre. A range of loads from 10 μN to 10,000 μN were applied to obtain the response from different depths of nacre. The values of hardness and elastic modulus decrease with increasing load (i.e., increase in penetration depth). The variation in these values is significant at lower loads and decreases with increase in indentation load. From our results, it appears that the nanoindentation tests done at lower loads are highly influenced by micro and nanostructure in nacre. The indentation experiments performed at low loads indicate an elastic modulus of about 15 GPa for the organic phase. The low load, low penetration experiments appear to be better indicators of nanomechanical behavior. Also, we have observed a step-like behavior in the load-displacement curves at high load indentations on nacre. These features are attributed to the organic layer between the aragonite platelets. The indentation tests with penetration depths more than ~250-300 nm often disrupt the organic layer and the behavior is not recovered in the unloading part of the curve. The microarchitecture and the composition of nacre contribute to the decrease in hardness values with increasing depth along with the indentation size effects.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. J.D. Currey: Mechanical properties of mother of pearl in tension. Proc. R. Soc. London, Ser. B Biol. Sci. 196, 443 (1977).

    Google Scholar 

  2. A.P. Jackson, J.F.V. Vincent, R.M. Turner: The mechanical design of nacre. Proc. R. Soc. London, Ser. B Biol. Sci. 234, 415 (1988).

    Google Scholar 

  3. A.P. Jackson, J.F.V. Vincent, R.M. Turner: Comparison of nacre with other ceramic composites. J. Mater. Sci. 25, 3173 (1990).

    Article  CAS  Google Scholar 

  4. J.D. Currey In The Mechanical Properties of Biological Materials, edited by J.F.V. Vincent and J.D. Currey (Cambridge University Press, London, 1980) p. 75.

  5. M. Yasrebi, G.M. Kim, K.E. Gunnison, D.L. Milius, M. Sarikaya, I.A. Aksay Bimomimetic processing of ceramics and ceramic-metal composites, in Better Ceramics Through Chemistry IV edited by B.J.J. Zelinski, C.J. Brinker, D.E. Clark, and D.R. Ulrich (Mater. Res. Soc. Symp. Proc. 180, Pittsburgh, PA, 1990), p. 625.

    CAS  Google Scholar 

  6. M. Sarikaya, K.E. Gunnison, M. Yasrebi, D.L. Milius, I.A. Aksay Mechanical properties-microstructure relationships in abalone shell, in Materials Synthesis Utilizing Biological Processes edited by P.C. Rieke, P.D. Calvert, and M. Alper (Mater. Res. Soc. Symp. Proc. 174, Pittsburgh, PA, 1999), p. 109.

    Google Scholar 

  7. K.S. Katti, M. Qian, D.W. Frech, M. Sarikaya: Electron energy loss spectroscopy and dielectric functions of geological and biological polymorphs of CaCO3. Microsc Microanal. 5, 358 (1999).

    Article  CAS  Google Scholar 

  8. D. Verma, K.S. Katti, and D.R. Katti: Photoacoustic FTIR spectroscopic study of undisturbed nacre from red abalone. Spectrochim. Acta (in press, 2005).

    Google Scholar 

  9. D.R. Katti, K.S. Katti: Modeling microarchitecture and mechanical behavior of nacre using 3D finite element techniques. J. Mater. Sci. 36, 1411 (2001).

    Article  CAS  Google Scholar 

  10. K.S. Katti, D.R. Katti, J. Tang, M. Sarikaya: Modeling mechanical responses in a laminated biocomposite. Part II. Nonlinear responses and nuances of nanostructure. J. Mater. Sci. 40, 1749 (2005).

    Article  CAS  Google Scholar 

  11. D.R. Katti, K.S. Katti, J.M. Sopp, M. Sarikaya: 3D finite element modeling of mechanical response in nacre-based hybrid nanocomposites. Comput. Theor. Polym. Sci. 11, 2485 (2001).

    Article  Google Scholar 

  12. D.R. Katti, S.M. Pradhan, K.S. Katti: Modeling the organic-inorganic interfacial nanoasperities in a model bio-nanocomposite, nacre. Rev. Adv. Mater. Sci. 6, 162 (2004).

    CAS  Google Scholar 

  13. K.S. Katti, D.R. Katti, S.M. Pradhan, A. Bhosle: Platelet interlocks are the key to toughness and strength in nacre. J. Mater. Res. 20, 1097 (2005).

    Article  CAS  Google Scholar 

  14. K.S. Katti, D.R. Katti Why is nacre so strong and tough? Mater. Sci. Eng., C (in press, 2006).

    Google Scholar 

  15. W.C. Oliver, G.M. Pharr: An improved technique for determining hardness and elastic-modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564 (1992).

    Article  CAS  Google Scholar 

  16. A.E. Giannakopoulos, S. Suresh: Determination of elastoplastic properties by instrumented sharp indentation. Script. Mater. 40, 1191 (1999).

    Article  CAS  Google Scholar 

  17. T.A. Venkatesh, Van K.J. Vliet, A.E. Giannakopoulos, S. Suresh: Determination of elasto-plastic properties by instrumented sharp indentation: Guidelines for property extraction. Script. Mater. 42, 833 (2000).

    Article  CAS  Google Scholar 

  18. X. Li, B. Bhusan: A review of nanoindentation continuous stiffness measurement technique and its applications. Mater. Charact. 48, 11 (2002).

    Article  CAS  Google Scholar 

  19. W.C. Oliver, G.M. Pharr: Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology. J. Mater. Res. 19, 3 (2004).

    Article  CAS  Google Scholar 

  20. Q. Ma, D.R. Clarke: Size dependent hardness in silver single crystals. J. Mater. Res. 10, 853 (1995).

    Article  CAS  Google Scholar 

  21. W.D. Nix, H. Gao: Indentation size effects in crystalline materials: A law for strain gradient plasticity. J. Mech. Phys. Solids 46, 411 (1998).

    Article  CAS  Google Scholar 

  22. K.W. McElhaney, J.J. Vlassak, W.D. Nix: Determination of indenter tip geometry and indentation contact area for depth-sensing indentation experiments. J. Mater. Res. 13, 1300 (1998).

    Article  CAS  Google Scholar 

  23. N.A. Stelmashenko, M.G. Walls, L.M. Brown, Y.V. Milman: Microindentation on W and Mo oriented single crystals: An STM study. Acta Metall. Mater. 41, 2855 (1993).

    Article  CAS  Google Scholar 

  24. T.Y. Zhang, W.H. Xu: Surface effects on nanoindentation. J. Mater. Res. 17, 1715 (2002).

    Article  CAS  Google Scholar 

  25. J.G. Swadener, E.P. George, G.M. Pharr: The correlation of the indentation size effect measured with indenters of various shaped. J. Mech. Phys. Solids 50, 681 (2002).

    Article  Google Scholar 

  26. A.J. Bushby, D.J. Dunstan: Plasticity size effects in nanoindentation. J. Mater. Res. 19, 137 (2004).

    Article  CAS  Google Scholar 

  27. Y. Wei, X. Wang, M. Zhao: Size effect measurement and characterization in nanoindentation test. J. Mater. Res. 19, 208 (2004).

    Article  CAS  Google Scholar 

  28. N.A. Fleck, J.W. Hutchinson: Strain gradient plasticity. Adv. Appl. Mech. 33, 295 (1997).

    Article  Google Scholar 

  29. H. Gao, Y. Huang, W.D. Nix, J.W. Hutchinson: Mechanism-based strain gradient plasticity-I. Theory J. Mech. Phys. Solids 47, 1239 (1999).

    Article  Google Scholar 

  30. Y. Huang, H. Gao, W.D. Nix, J.W. Hutchinson: Mechanism-based strain gradient plasticity-II. Anal. J. Mech. Phys. Solids 48, 99 (2000).

    Article  Google Scholar 

  31. R.O. Ritchie, J.J. Kruzic, C.L. Muhlstein, R.K. Nalla, E.A. Stach: Characteristic dimensions and the micro-mechanisms of fracture and fatigue in “nano” and “bio” materials. Int. J. Fracture 128, 1 (2004).

    Article  CAS  Google Scholar 

  32. X. Li, P. Nardi: Micro/nanomechanical characterization of a natural nanocomposite material: The shell of Pectinidae. Nanotechnology 15, 211 (2004).

    Article  Google Scholar 

  33. X. Li, W. Chang, Y.J. Chao, R. Wang, M. Chang: Nanoscale structural and mechanical characterization of a natural nanocomposite material: The shell of red abalone. Nano Lett. 4, 613 (2004).

    Article  CAS  Google Scholar 

  34. B.J.F. Bruet, R. Panas, K. Tai, C. Ortiz, H.J. Qi, M.C. Boyce: Nanoscale morphology and indentation of individual nacre tablets from the gastropod mollusk Trochus Niloticus. J. Mater. Res. 20, 2400 (2005).

    Article  CAS  Google Scholar 

  35. D.L. Joslin, W.C. Oliver: A new method for analyzing data from continuous depth sensing microindentation test. J. Mater. Res. 5, 123 (1990).

    Article  CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Kalpana S. Katti.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Katti, K.S., Mohanty, B. & Katti, D.R. Nanomechanical properties of nacre. Journal of Materials Research 21, 1237–1242 (2006). https://doi.org/10.1557/jmr.2006.0147

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1557/jmr.2006.0147

Navigation