Discontinuous Ablation Behavior of Four-Directional Dual-Matrix C/C Composites under Dual-Pulse Solid Rocket Motors

The ablation resistance of the composites was evaluated through ablation testing in a dual-pulse solid rocket motor, and their discontinuous ablation behavior was investigated. The results showed that the carbon rods in the composites exhibited a hexagonal shape, with a dense pyrolytic carbon "wall" structure formed around them.

The unilateral linear ablation rates of the composites after pulse I and pulse II were 0.068 mm/s and 0.113 mm/s, respectively. The cellular-like PyC layer and nanowire structures deposited during the ablation process were attached to the surface of the throat convergent section, while cracks and delamination occurred on and within the divergent section. The ablation of C/C composites under dual-pulse rocket motor conditions involved a complex process, including high-temperature, high-speed gas scouring, oxygen-containing thermochemical ablation, and thermal shock.