Tablet-level origin of toughening in abalone shells and translation to synthetic composite materials

Horacio D. Espinosa, Allison L. Juster, Felix J. Latourte, Owen Y. Loh, David Gregoire, Pablo D. Zavattieri

Research output: Contribution to journalArticlepeer-review

339 Scopus citations

Abstract

Nacre, the iridescent material in seashells, is one of many natural materials employing hierarchical structures to achieve high strength and toughness from relatively weak constituents. Incorporating these structures into composites is appealing as conventional engineering materials often sacrifice strength to improve toughness. Researchers hypothesize that nacre's toughness originates within its brick-and-mortar-like microstructure. Under loading, bricks slide relative to each other, propagating inelastic deformation over millimeter length scales. This leads to orders-of-magnitude increase in toughness. Here, we use in situ atomic force microscopy fracture experiments and digital image correlation to quantitatively prove that brick morphology (waviness) leads to transverse dilation and subsequent interfacial hardening during sliding, a previously hypothesized dominant toughening mechanism in nacre. By replicating this mechanism in a scaled-up model synthetic material, we find that it indeed leads to major improvements in energy dissipation. Ultimately, lessons from this investigation may be key to realizing the immense potential of widely pursued nanocomposites.

Original languageEnglish (US)
Article number173
JournalNature communications
Volume2
Issue number1
DOIs
StatePublished - 2011

Funding

We gratefully acknowledge Scott Webb of the GM Research and Development Center for fabrication of the ABS samples, and Dr Alexander Moravsky for fruitful discussions on polymers and auxetic materials. We also gratefully acknowledge Dr Mohammad Naraghi for his assistance in characterizing the ABS samples. H.D.E. acknowledges the support of the National Science Foundation through award No. CMS-0301416, General Motors Company through contract No. TCS10643, ARO through MURI Award No. W911NF-09-1-0541 and ONR through Award Nos. N00014-08-1-0108, N00014-07-1-1139 and N00014-08-1-1055. Special thanks to Mark Seniw and Carla Shute for assistance with sample preparation and material testing. A.L.J. acknowledges the Northwestern University ISEN Cluster Fellowship. O.Y.L. acknowledges the Northwestern University Presidential and Ryan Fellowships.

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy

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