Ceramic Matrix Composite Cyclic Ablation Behavior under Oxyacetylene Torch.

ABSTRACT

To study the ablation properties and differences of plain-woven SiC/SiC composites under single and cyclic ablation. The ablation test of plain-woven SiC/SiC composites was conducted under an oxyacetylene torch. The results indicate that the mass ablation rate of cyclic ablation is lower than that of single ablation, whereas the line ablation rate is higher. Macro-microstructural characterization revealed the presence of white oxide formed by silica on the surface of the ablation center region. The fibers in the central region of the ablation were ablated layer by layer, and the broken fiber bundles exhibited a spiky morphology with numerous silica particles attached. The oxide layer on the surface and the silica particles on the fibers, which are in the molten state formed in the high-temperature ablation environment, contribute to resisting ablation. Thermal shock during cyclic ablation also played a role in the ablation process. The thermal shock causes cracks in the fiber bundles and matrix of the SiC/SiC composites. This study helps to apply SiC/SiC composite to complex thermal shock environments.