Hierarchical toughening of bioinspired nacre-like hybrid carbon composite

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. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The study demonstrates the construction of multiscale micro/nano-architectures in a hybrid composite material containing two different carbon forms, showing remarkable mechanical efficiency with good damage tolerance and rising R-curve behavior. This verifies the potential of nacre-inspired designs for enhancing fracture toughness in carbon systems.