Fracture nacre

Fig. 5 The proteinaceous filaments that arc pulled out cf the organic binding layer between separated sheets of aragonite in nacre (a) extend in a stepwise manner, as revealed by force measurements with the atomic force microscope (b). The sawtooth stress-strain curve creates a greater work of fracture (area below the curve) than that for either a short, stiff adhesive strand or a long, smoothly elastic one. (After Ref. [26].) View this art in color at www.dekker.com.)...

If we compare the increase in fracture toughness that has been achieved in nacre to those obtained in technical ceramics (see table 7.4), it is rather obvious that it would be highly desirable to technically exploit the same strengthening mechanisms. This is one reason for the strong scientific interest in nacre. The main aim of these studies is to create artificial materials with similar prop>-erties. Such materials, which mimic the properties of biological materials, are called biomimetic materials. 

Figure 3. Fracture surface of abalone nacre (matrix removed).

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