Laminated Microstructure and Toughness Mechanism of Abalone Shell

SEM observation on an abalone shell shows that the shell is a kind of bioceramic composite consisting of inorganic aragonite sheets and organic collagen protein matter. The aragonite sheets possess long and thin shape and are divided by the collagen protein matter, which compose a kind of laminated microstructure of the shell. The fracture surface energy of the laminated microstructure is investigated and compared with non-laminated microstructure based on its representative model. It shows that the fracture surface energy of the laminated microstructure is markedly larger than that of the non-laminated microstructure and endows the shell with high fracture toughness.