Novel Composite Microstructure and Mechanical Behavior of Mollusk Shell

Abstract

Preliminary investigations of the microstructure/mechanical properties relationship in a mollusk shell—the large conch, Strombus gigas —are reported. Strombus gigas has the well‐ordered “crossed lamellar” microstructure and, in four‐point bending, is remarkably tough in certain orientations, permitting noncatastrophic (“graceful”) failure. Fractography indicates that several toughening mechanisms are acting in concert, including crack bridging, microcracking, fiber pullout, and microstructurally induced crack arrest branching. Microindentation studies show that this material is very resistant to cracking; the damage zones around the indents strongly reflect the lamellar character of the microstructure.