Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-28T20:15:55.576Z Has data issue: false hasContentIssue false

Nanomechanical properties of nacre

Published online by Cambridge University Press:  01 May 2006

Kalpana S. Katti*
Affiliation:
Department of Civil Engineering, North Dakota State University, Fargo, North Dakota 58105
Bedabibhas Mohanty
Affiliation:
Department of Civil Engineering, North Dakota State University, Fargo, North Dakota 58105
Dinesh R. Katti
Affiliation:
Department of Civil Engineering, North Dakota State University, Fargo, North Dakota 58105
*
a) Address all correspondence to this author. e-mail: Kalpana.Katti@ndsu.edu
Get access

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.

Type
Articles
Copyright
Copyright © Materials Research Society 2006

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.Currey, J.D.: Mechanical properties of mother of pearl in tension. Proc. R. Soc. London, Ser. B Biol. Sci. 196, 443 (1977).Google Scholar
2.Jackson, A.P., Vincent, J.F.V., Turner, R.M.: The mechanical design of nacre. Proc. R. Soc. London, Ser. B Biol. Sci. 234, 415 (1988).Google Scholar
3.Jackson, A.P., Vincent, J.F.V., Turner, R.M.: Comparison of nacre with other ceramic composites. J. Mater. Sci. 25, 3173 (1990).CrossRefGoogle Scholar
4.Currey, J.D. In The Mechanical Properties of Biological Materials, edited by Vincent, J.F.V. and Currey, J.D. (Cambridge University Press, London, 1980) p. 75.Google Scholar
5.Yasrebi, M., Kim, G.M., Gunnison, K.E., Milius, D.L., Sarikaya, M., Aksay, I.A. Bimomimetic processing of ceramics and ceramic-metal composites, in Better Ceramics Through Chemistry IV edited by Zelinski, B.J.J., Brinker, C.J., Clark, D.E., and Ulrich, D.R. (Mater. Res. Soc. Symp. Proc. 180, Pittsburgh, PA, 1990), p. 625.Google Scholar
6.Sarikaya, M., Gunnison, K.E., Yasrebi, M., Milius, D.L., Aksay, I.A. Mechanical properties-microstructure relationships in abalone shell, in Materials Synthesis Utilizing Biological Processes edited by Rieke, P.C., Calvert, P.D., and Alper, M. (Mater. Res. Soc. Symp. Proc. 174, Pittsburgh, PA, 1999), p. 109.Google Scholar
7.Katti, K.S., Qian, M., Frech, D.W., Sarikaya, M.: Electron energy loss spectroscopy and dielectric functions of geological and biological polymorphs of CaCO3. Microsc Microanal. 5, 358 (1999).Google Scholar
8.Verma, D., Katti, K.S., and Katti, D.R.: Photoacoustic FTIR spectroscopic study of undisturbed nacre from red abalone. Spectrochim. Acta (in press, 2005).CrossRefGoogle Scholar
9.Katti, D.R., Katti, K.S.: Modeling microarchitecture and mechanical behavior of nacre using 3D finite element techniques. J. Mater. Sci. 36, 1411 (2001).Google Scholar
10.Katti, K.S., Katti, D.R., Tang, J., Sarikaya, M.: Modeling mechanical responses in a laminated biocomposite. Part II. Nonlinear responses and nuances of nanostructure. J. Mater. Sci. 40, 1749 (2005).Google Scholar
11.Katti, D.R., Katti, K.S., Sopp, J.M., Sarikaya, M.: 3D finite element modeling of mechanical response in nacre-based hybrid nanocomposites. Comput. Theor. Polym. Sci. 11, 2485 (2001).Google Scholar
12.Katti, D.R., Pradhan, S.M., Katti, K.S.: Modeling the organic-inorganic interfacial nanoasperities in a model bio-nanocomposite, nacre. Rev. Adv. Mater. Sci. 6, 162 (2004).Google Scholar
13.Katti, K.S., Katti, D.R., Pradhan, S.M., Bhosle, A.: Platelet interlocks are the key to toughness and strength in nacre. J. Mater. Res. 20, 1097 (2005).Google Scholar
14.Katti, K.S., Katti, D.R. Why is nacre so strong and tough? Mater. Sci. Eng., C (in press, 2006).CrossRefGoogle Scholar
15.Oliver, W.C., Pharr, G.M.: An improved technique for determining hardness and elastic-modulus using load and displacement sensing indentation experiments. J. Mater. Res. 7, 1564 (1992).Google Scholar
16.Giannakopoulos, A.E., Suresh, S.: Determination of elastoplastic properties by instrumented sharp indentation. Script. Mater. 40, 1191 (1999).Google Scholar
17.Venkatesh, T.A., Van Vliet, K.J., Giannakopoulos, A.E., Suresh, S.: Determination of elasto-plastic properties by instrumented sharp indentation: Guidelines for property extraction. Script. Mater. 42, 833 (2000).Google Scholar
18.Li, X., Bhusan, B.: A review of nanoindentation continuous stiffness measurement technique and its applications. Mater. Charact. 48, 11 (2002).Google Scholar
19.Oliver, W.C., Pharr, G.M.: Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology. J. Mater. Res. 19, 3 (2004).Google Scholar
20.Ma, Q., Clarke, D.R.: Size dependent hardness in silver single crystals. J. Mater. Res. 10, 853 (1995).Google Scholar
21.Nix, W.D., Gao, H.: Indentation size effects in crystalline materials: A law for strain gradient plasticity. J. Mech. Phys. Solids 46, 411 (1998).CrossRefGoogle Scholar
22.McElhaney, K.W., Vlassak, J.J., Nix, W.D.: Determination of indenter tip geometry and indentation contact area for depth-sensing indentation experiments. J. Mater. Res. 13, 1300 (1998).CrossRefGoogle Scholar
23.Stelmashenko, N.A., Walls, M.G., Brown, L.M., Milman, Y.V.: Microindentation on W and Mo oriented single crystals: An STM study. Acta Metall. Mater. 41, 2855 (1993).Google Scholar
24.Zhang, T.Y., Xu, W.H.: Surface effects on nanoindentation. J. Mater. Res. 17, 1715 (2002).Google Scholar
25.Swadener, J.G., George, E.P., Pharr, G.M.: The correlation of the indentation size effect measured with indenters of various shaped. J. Mech. Phys. Solids 50, 681 (2002).Google Scholar
26.Bushby, A.J., Dunstan, D.J.: Plasticity size effects in nanoindentation. J. Mater. Res. 19, 137 (2004).Google Scholar
27.Wei, Y., Wang, X., Zhao, M.: Size effect measurement and characterization in nanoindentation test. J. Mater. Res. 19, 208 (2004).Google Scholar
28.Fleck, N.A., Hutchinson, J.W.: Strain gradient plasticity. Adv. Appl. Mech. 33, 295 (1997).CrossRefGoogle Scholar
29.Gao, H., Huang, Y., Nix, W.D., Hutchinson, J.W.: Mechanism-based strain gradient plasticity-I. Theory J. Mech. Phys. Solids 47, 1239 (1999).Google Scholar
30.Huang, Y., Gao, H., Nix, W.D., Hutchinson, J.W.: Mechanism-based strain gradient plasticity-II. Anal. J. Mech. Phys. Solids 48, 99 (2000).CrossRefGoogle Scholar
31.Ritchie, R.O., Kruzic, J.J., Muhlstein, C.L., Nalla, R.K., Stach, E.A.: Characteristic dimensions and the micro-mechanisms of fracture and fatigue in “nano” and “bio” materials. Int. J. Fracture 128, 1 (2004).Google Scholar
32.Li, X., Nardi, P.: Micro/nanomechanical characterization of a natural nanocomposite material: The shell of Pectinidae. Nanotechnology 15, 211 (2004).Google Scholar
33.Li, X., Chang, W., Chao, Y.J., Wang, R., Chang, M.: Nanoscale structural and mechanical characterization of a natural nanocomposite material: The shell of red abalone. Nano Lett. 4, 613 (2004).Google Scholar
34.Bruet, B.J.F., Panas, R., Tai, K., Ortiz, C., Qi, H.J., Boyce, M.C.: Nanoscale morphology and indentation of individual nacre tablets from the gastropod mollusk Trochus Niloticus. J. Mater. Res. 20, 2400 (2005).Google Scholar
35.Joslin, D.L., Oliver, W.C.: A new method for analyzing data from continuous depth sensing microindentation test. J. Mater. Res. 5, 123 (1990).CrossRefGoogle Scholar