Effects of interlaminar modification on mechanical, thermal conductivity and ablative performance of C/C composites doped with high thermal conductivity graphite film

Abstract

C/C composites modified with high thermal conductivity graphite film (C/C-HTCGF) were prepared by resin impregnation‑carbonization and chemical vapor infiltration. Effects of interlaminar HTCGF modification on microstructure, mechanical, thermal conductivity (TC) and ablative properties were investigated. The findings demonstrate that the interlaminar HTCGF modification not only affects the flexural and compressive strength, but also results in the pseudoplastic behavior for the composites. After 3000 °C graphitization, the flexural and compressive strength drop from 109.81 and 142.4 MPa to 88.49 and 60.5 MPa, respectively, which can be attributed to the increased defects (cracks and pores) and degraded carbon fibers' strength in the composites. Meanwhile, the TC of the composites increases from 56.929 to 160.569 W/ (m·K) and 12.452 to 38.839 W/(m·K) in both transverse direction and thickness direction due to the increased graphitization degree. Moreover, the enhanced TC after graphitization declines the maximum surface temperature (110 °C) during ablation.