Investigation on ablation/erosion of 5D carbon/carbon composites

The star-style AC arc heater was employed as the ground simulation system to investigate the ablation and erosion behavior of 5D carbon/carbon(C/C) composites. The ablation behavior was analyzed through observing the ablative surface temperatures and the material microstructures after ablation. The results show that under the effect of ablation/erosion coupling, the heating rate of ablative surface and the ablation equilibrium temperature increased, and the later increased about 200~300°C. The internal microstructure of 5D C/C led to non-uniform ablation of fibers, matrix and interface. The interface ablation destroyed the connection between the fiber bundle and the matrix, which made the fiber bundle and the matrix lose the support and form the ablation surface delaminates. A small amount of Al ₂O ₃ particle deposited on the ablation surface. The fibers, which were perpendicular to the ablation surface, exposed and broke on account of the particle impact bending momentum. There were no acicular fiber structures compared with the thermo-chemical ablation, and the fiber fracture was flat. Particle erosion not only decreased the quality of the materials directly, but also made the surface loosen, which promoted the thermo-chemical ablation and mechanical erosion behavior, in addition, the linear ablation rate was also significantly increased.