Cracking the mystery of nature’s toughest material

Science Daily  October 23, 2019
Nacre (mother-of-pearl) that lines the insides of mussel and other mollusk shells is known as nature’s toughest material. An international team of researchers (USA – University of Michigan, Australia, Germany) found that nacre is made of microscopic bricks made of a mineral called aragonite, laced together with a mortar made of organic material. The tablets remain separate, arranged in layers. When stress is applied to the shells, the mortar squishes aside and the tablets lock together, forming a solid surface. When the force is removed, the structure springs back, without losing any strength or resilience. Nacre lost none of its resilience in repeated impacts at up to 80% of its yield strength. If a crack does form, nacre confines the crack to a single layer rather than allowing it to spread, keeping the shell’s structure intact. The researchers believe that humans could use the mussel’s methods to create nano-engineered composite surfaces that could be dramatically lighter and stronger than those available today…read more. Open Access TECHNICAL ARTICLE