Nanoscale deformation mechanics reveal resilience in nacre of Pinna nobilis shell
Nanoscale deformation mechanics reveal resilience in nacre of Pinna nobilis shell
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DOI：
10.1038/s41467-019-12743-z
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发表时间：
2019-10-23
影响因子：
16.6
通讯作者：
Hovden, Robert
中科院分区：
文献类型：
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作者：
Gim, Jiseok;Schnitzer, Noah;Hovden, Robert
软纳米级有机组分与由天然生物体分级设计的无机纳米颗粒的组合导致高度延展性的结构材料，其可以承受机械冲击并在宏观和纳米尺度上表现出高弹性。我们对珍珠层变形的研究揭示了控制结构弹性和机械能吸收的潜在纳米力学。使用高分辨率扫描/透射电子显微镜（S/TEM）结合原位压痕，我们观察到纳米级恢复严重变形的珍珠层，恢复其机械强度的外部刺激高达80%的屈服强度。在压缩下，珍珠质经历纳米颗粒的变形和跨越有机界面的非破坏性锁定，使得相邻的无机片在结构上结合。锁片作为一种连续的材料对应变作出反应，但它们之间的有机边界仍然限制裂纹的扩展。值得注意的是，完全锁定的接口恢复其原始形态没有任何明显的变形后，压缩接触应力高达1.2 GPa。
The combination of soft nanoscale organic components with inorganic nanograins hierarchically designed by natural organisms results in highly ductile structural materials that can withstand mechanical impact and exhibit high resilience on the macro- and nano-scale. Our investigation of nacre deformation reveals the underlying nanomechanics that govern the structural resilience and absorption of mechanical energy. Using high-resolution scanning/transmission electron microscopy (S/TEM) combined with in situ indentation, we observe nanoscale recovery of heavily deformed nacre that restores its mechanical strength on external stimuli up to 80% of its yield strength. Under compression, nacre undergoes deformation of nanograins and non-destructive locking across organic interfaces such that adjacent inorganic tablets structurally join. The locked tablets respond to strain as a continuous material, yet the organic boundaries between them still restrict crack propagation. Remarkably, the completely locked interface recovers its original morphology without any noticeable deformation after compressive contact stresses as large as 1.2 GPa.