Mechanical properties and microstructure of tortoise shell

Abstract

In the present paper, the mechanical properties and microstructure of tortoise shell are investigated in detail. The maximum flexural strength is found to be 165.1 MPa and the fracture toughness is 36.4 MPa m^1/2. These excellent properties are a result of its complex microstructure, which comprises not only inorganic, brittle and rigid elongated crystals of hydroxy apatite but also organic tough films and fibres. Microstructural characteristics vary greatly within different parts of the shell. Results from this study are expected to provide beneficial information on tailoring of artificial composites.