Dr. Phani Nukala
Nacre exhibits phenomenal fracture strength and toughness properties despite its relatively weak material properties. Its work of fracture is about 3000 times greater than that of a single crystal of its constituent mineral. This is surprising because it is a ceramic composite made up of 95% brittle calcium carbonate (CaCO3) and 5% of a biopolymer material (organic glue).
Today, synthetic polymer-matrix composites with such high levels of ceramic fillers do not possess these exceptional combinations of stiffness, fracture strength and toughness. Understanding the mechanisms of such high damage tolerance of nacre will enhance our ability to design novel materials for innovative practical applications. Research on synthesizing such tough materials is currently under intense development at Oak Ridge National Laboratory and elsewhere, since these materials can be used as light-weight body armor and in various defense related applications.