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详细分析和比较了3D炭/炭复合材料及其添加难熔金属碳化物的试样在三种烧蚀条件下的烧蚀结果、微观结构及形貌。SEM观察结果显示,纤维与基体间的界面优先烧蚀现象对纯炭/炭试样是普遍存在的,相反,对难熔金属碳化物掺杂的炭/炭试样而言,纤维却总是优先被烧蚀;纤维单丝相对基体优先烧蚀越明显,材料宏观烧蚀率越大。对纯炭/炭试样烧蚀表层区的TEM观察结果表明,在烧蚀过程中炭纤维和基体炭均发生明显的微观结构变化,具体表现为炭纤维的微晶尺寸显著长大,而基体炭原有层片区则出现柱状炭。烧蚀测试条件对材料宏观和微观形貌及烧蚀机理都有影响。
The ablation results, microstructure and morphology of 3D carbon / carbon composites and their samples with refractory metal carbides were analyzed and compared in detail. SEM observations show that the preferential ablation at the interface between the fibers and the matrix is ubiquitous for pure carbon / carbon samples. In contrast, for carbon / carbon samples doped with refractory metal carbides, the fibers are always Giving priority to being ablated; the preferential ablation of the fiber monofilament relative to the substrate is more obvious, and the greater the macroscopic ablation rate of the material is. TEM observation of the ablated surface area of the pure carbon / carbon sample shows that both the carbon fiber and the matrix carbon undergo obvious microstructure changes during the ablation process, and the crystallite size of the carbon fiber significantly grows while the size of the matrix The original layer of carbon layer appears columnar carbon. Ablation test conditions on the material macroscopic and microscopic morphology and ablation mechanism has an impact.