Thermophysical and ablative properties of axial carbon rod weaved 4D carbon/carbon composites

A kind of high-density C/C composite reinforced by carbon fiber and axial carbon rod mix weaved 4D perform was prepared by the process of high-pressure pitch impregnation and carbonization. The thermophysical and ablative properties of the 4D C/C composites in axial direction were investigated. The results show that with increasing temperature the thermal diffusivity of the composites decreases exponentially, the specific heat increases, and the thermal conductivity decreases linearly, and the thermal constants will tend to steadily at high temperature. The 4D C/C composites exhibit a negative coefficient of thermal expansion at low temperature, which increases with increasing temperature. After 120 s oxygen-ethyne ablation, the mass ablation rate and linear ablation rate is 2.04 × 10^-3g · s^-1 and 3.92 × 10^-3 mm · s^-1, respectively. The ablation mechanism of the 4D C/C composites is mainly a synergistic effect of thermo-chemical ablation and mechanical erosion.