多向编织炭/炭的复合材料烧蚀性能

Ablative performance of 3D carbon/carbon composites

利用以星型交流电弧加热器为核心的地面模拟系统对三维5D编织炭/炭复合材料的烧蚀行为进行了考核,通过对材料烧蚀表面温度、形貌的在线实时监测及烧蚀后微观结构的观察,研究了该类材料的烧蚀行为.研究发现:三维5D编织炭/炭复合材料的烧蚀是热化学烧蚀和机械剥蚀的综合作用,构件边缘区域以机械剥蚀为主,中心区域表现为热化学烧蚀和机械剥蚀相互耦合,没有明确的分界;基体炭与炭纤维的抗烧蚀性能相差较大,炭纤维的抗热化学烧蚀性能、抗机械剥蚀性能明显高于基体炭,烧蚀后试件烧蚀表面仅剩下凸起的纤维束骨架结构;三维5D编织炭/炭复合材料的烧蚀性能表现出较强的各向异性,在轴向体现为单根纤维失去周围基体支持而发生剥离,抗烧蚀性能相比较好;在径向体现为烧蚀表面脱层,抗烧蚀性能相比较差.

The present paper is concerned with the evaluation of ablative performance of 3D carbon/carbon composites. The morphology and microstructure of ablative samples are investigated by on-line real-time monitoring system and SEM techniques. The results show that the ablation of 3D C/C composites is as a result of integration of thermo-chemical ablation and mechanical denudation. Mechanical denudation is dominant at the edge of sample surface, and while thermo-ehemical ablation and mechanical denudation are coupled in the center region of sample surface. It has obvious discrepancy for ablative performance between carbon matrix and carbon fiber. The ablation resistance of carbon fiber is much better than the carbon matrix＇ s. The ablative performance of3D C/C composites displays clear anisotropy. It is better in the longitudinal direction of 3D C/ Cs because the fiber bundle-can resist the ablation until it loses the support of the surrounding matrix. On the contrary, the ablation resistance is poor in the radial direction of 3D C/Cs because the surface delamination is dominant in the course of ablation.