One-step construction of three-dimensional disordered graphene-like pyrolytic carbon composites by oxygen controllable chemical vapor deposition

Multi-scale reinforcement strategies have been widely integrated in the preparation of high-performance composites for high strength and functionality, but it is challenging to achieve the microstructurally adjustable and the feasible design of modulus matching between the matrix and the nano-reinforcements. Herein, we integrated the preparation of graphene nano-reinforcements with pyrolytic carbon matrix by a one-step oxygen controllable chemical vapor deposition (OCCVD) process and designed a multi-step gradient of the modulus carbon composite. Furthermore, the microstructure morphology and the deep molecular insights under different oxygen contents were obtained by simulating the OCCVD process based on reactive molecular dynamics. Additionally, the modulus and fracture strength of different carbon structures were acquired by corresponding mechanical simulations. On this basis, the experimentally designed and prepared multiscale carbon/carbon composites simultaneously exhibited excellent flexural mechanical properties and matrix deformation capacity compared with the conventional carbon/carbon composites. The interpenetrating structural features of the prepared composites promote a high level of interfacial shear resistance, resulting in significantly enhanced load transfer strengthening as well as crack-bridging toughening. Our method provides new insights into the chemical vapor deposition process and a new way of thinking about the fabrication of high specific strength composites with great simplicity and versatility.