Abstract Replicating the architecture of natural nacre has become an important approach for enhancing the damage tolerance of man-made materials. Nevertheless, this is principally limited to systems composed of chemically different constituents and demonstrates a difficulty in realizing structural hierarchy at multiple length-scales. Here a proof of concept is presented about the implementation of bioinspired nacre-like designs in a hybrid composite of pure carbon comprising its two basic allotropic forms, i.e., natural graphite flakes and amorphous carbon from the carbonization of organics. Multiscale micro/nano-architectures with three levels of hierarchy were constructed in the composite based on the preferential alignment of graphite flakes using bidirectional freeze casting method. The composite exhibited a remarkable mechanical efficiency, specifically featured by good damage tolerance with rising R-curve behavior, owing to the activation of hierarchical toughening mechanisms at micro to nano length-scales. This verifies the potency of nacre-inspired designs for generating enhanced fracture toughness in carbon systems, even using simple raw materials, which is significant for promoting their structural applications.

中文翻译：

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仿生珍珠层状杂化碳复合材料的分级增韧

摘要 复制天然珍珠层的结构已成为提高人造材料抗损伤能力的重要途径。然而，这主要限于由不同化学成分组成的系统，并证明难以在多个长度尺度上实现结构层次。这里提出了关于在纯碳的混合复合材料中实施仿生珍珠层设计的概念证明，该复合材料包括其两种基本的同素异形体形式，即天然石墨薄片和来自有机物碳化的无定形碳。基于使用双向冷冻铸造方法优先排列的石墨薄片，在复合材料中构建了具有三个层次结构的多尺度微/纳米结构。该复合材料表现出显着的机械效率，由于在微米到纳米长度尺度上激活了分级增韧机制，因此具有良好的损伤耐受性和上升的 R 曲线行为。这验证了受珍珠层启发的设计在碳系统中产生增强的断裂韧性的效力，即使使用简单的原材料，这对于促进其结构应用也具有重要意义。