Ablation behaviour and mechanical property of the B-modified SiC/HfC-SiC composites in cyclic ablation environment.

• B-modified SiC/HfC-SiC composite has been fabricated by the combination of PIP and CVD. • The bending strength of cyclic ablated SiC/HfC-SiC and B-modified SiC/HfC-SiC composites have been characterized. • Effective residual thickness is proposed in this paper to present ablative dimensional stability. • After introducing boron, the effective residual thickness of ablated SiC/HfC-SiC composite increased significantly. The B-modified SiC/HfC-SiC composites were prepared by the combination of precursor infiltration and pyrolysis (PIP) and chemical vapor deposition (CVD) methods. The microstructure, cyclic ablation and bending strength tests of the SiC/HfC-SiC composites with and without B were investigated. The results showed that the B-modified composites had a better cyclic ablation resistance than that of the composites without B. The effective residual thickness of the B-modified composites was also higher than that of the composites without B after cyclic ablation. The residual bending strength of the B-modified composites was slightly lower than that of the composites without B. [ABSTRACT FROM AUTHOR]