Nature utilizes the available resources to construct lightweight, strong and tough materials under constrained environmental conditions. The impact surface of the fast-striking dactyl club from the mantis shrimp is an example of one such composite material; the shrimp has evolved the capability to localize damage and avoid catastrophic failure from high-speed collisions during its feeding activities. Here we report that the dactyl club of mantis shrimps contains an impact-resistant coating composed of densely packed (about 88 per cent by volume) ~65-nm bicontinuous nanoparticles of hydroxyapatite integrated within an organic matrix. These mesocrystalline hydroxyapatite nanoparticles are assembled from small, highly aligned nanocrystals. Under impacts of high strain rates (around 10⁴ s⁻¹), particles rotate and translate, whereas the nanocrystalline networks fracture at low-angle grain boundaries, form dislocations and undergo amorphization. The interpenetrating organic network provides additional toughening, as well as substantial damping, with a loss coefficient of around 0.02. An unusual combination of stiffness and damping is therefore achieved, outperforming many engineered materials.

大自然利用有限的环境条件下可用的资源来构造轻质，坚固和坚韧的材料。螳螂虾的速击式Dactyl棍棒的撞击表面就是这种复合材料的一个例子。虾已经发展了定位损害的能力，并避免了在喂食活动中因高速碰撞而导致的灾难性故障。在这里我们报告说，螳螂虾的Dactyl club包含一个耐冲击涂层，该涂层由紧密堆积（约占体积的88％）〜65 nm的羟基磷灰石双连续纳米颗粒集成在有机基质中组成。这些介晶的羟基磷灰石纳米粒子是由小的，高度排列的纳米晶体组装而成的。在高应变率的冲击下（约10 ⁴  s ^-1），粒子旋转和平移，而纳米晶网络在低角度晶界破裂，形成位错并经历非晶化。互穿的有机网络可提供额外的增韧效果，以及显着的阻尼，损耗系数约为0.02。因此，获得了刚度和阻尼的非凡组合，胜过许多工程材料。