高温处理对液相气化沉积碳/碳复合材料微观组织结构及力学性能的影响

 对用快速液相气化法制备的碳 /碳复合材料进行了石墨化处理;用 X-ray衍射技术和扫描电子显微镜对高温处理前后材料的微观组织结构及断口形貌进行了研究观察;分析了影响石墨化前后微观结构、力学性能变化及断裂失效模式的因素及机理。结果表明 :经石墨化处理后,d₀₀₂ 值降低,L_c 值升高,弯曲强度σ_f大幅度降低,层间剪切强度 ILSS升高,但随热处理温度提高,ILSS值有降低趋势。

INFLUENCE OF HIGH TEMPERATURE TREATMENT ON MICROSTRUCTUREAND MECHANICAL PROPERTIES OF 2D-C/C COMPOSITES PREPARED BYLIQUID-VAPORIZED PROCESSING

D-C/C composites fabricated by a rapid densification process-Liquid-Vaporized CVI were heat treated at various high temperatures. The microstructural change and graphitability of the pyrocarbon matrix were studied with X-ray diffraction (XRD) technology; changes in mechanical properties and fracture behaviour were correlated with scanning electron microscopy (SEM) observations of fracture surfaces, fiber and matrix microstructures, and fiber/matrix interfacial structures. It was confirmed from XRD that the interlaminar distance of (002) planes (d₀₀₂) decreased from 3.501Åto 3.376Å; the microcrystalline stack height (L_c) increased; flexural strength was found to decrease drastically, while interlaminar shear strength (ILSS) to increase obviously after graphitization, and at the same time, the fracture toughness to increase.