Microstructure and Mechanical Properties of Multilayer-textured 2D Carbon/Carbon Composites

Two-dimensional (2D) carbon/carbon (C/C) composites with multilayered texture, especially with different thickness of high-textured (HT) pyrocarbon layer, were prepared by isothermal, isobaric chemical vapor infiltration (CVI) technique. The influence of matrix microstructure on mechanical properties of C/C composites was investigated by polarized light microscopy, scanning electron microscopy and three-point bending test. The results show that the samples with multilayer-textured pyrocarbon matrix own a higher flexural strength than the one with pure medium-textured structure, which is attributed to multiple crack deflection and interfacial sliding between different textured pyrocarbon layers and between sub-layers within HT layer. The increase in thickness of HT pyrocarbon layer improves the plasticity of the samples and renders the fracture in pseudo-plastic behavior.