▎ 摘　　要

The effects of reinforced structure (three-dimensional braided preform and laminated plain woven fabric) and graphene nanoplatelet-reinforced hierarchical interface on the impact properties of carbon fabric composites after thermo-oxidative aging were investigated. The results indicated that the impact properties decreased with increasing aging time due to the degradation of the matrix and fiber-matrix interface. After exposure to 140 degrees C for 1200 h, the peak impact force and impact strength retention rates of 3D-braided graphene nanoplatelet-coated carbon fiber-reinforced composite were 13% and 8% higher than those of the laminated composite, respectively. One of the reasons was the graphene nanoplatelet-reinforced gradient interphase may provide an effective shield against interface oxidation, transfer the localized thermal stress, and restrict the movement of the different phase of the materials at the composites interface. Another reason was the integrated structure of the 3D-braided composite can make the fiber bear impact force together although the resin was damaged and the adhesive force between fiber bundles and resin decreased after thermo-oxidative aging. This synergetic reinforcing effect of 3D-braided structure and graphene nanoplatelet-reinforced hierarchical interface provides an easy and effective way to design and improve the thermo-oxidative stability of carbon fiber-reinforced composites.