中间相沥青基碳纤维石墨化度对Cf/Al界面损伤的影响

以不同石墨化度的中间相沥青基碳纤维为基底磁控溅射构筑Cf/Al界面,研究了不同石墨化度Cf/Al界面微观结构的演变,并与聚丙烯腈碳纤维比较揭示了Cf/Al界面的损伤机制。结果表明：随着石墨化处理温度的提高中间相沥青基碳纤维的石墨微晶尺寸增大、取向度和石墨化度提高,Cf/Al界面的反应程度降低和碳纤维损伤减少。不同石墨化度Cf/Al界面的损伤决定于初始缺陷的数量和后续裂纹在碳纤维内部的增殖和扩展。在2400℃和2700℃石墨化处理使裂纹更容易在中间相沥青基碳纤维石墨微晶片层间扩展,去除镀层后纤维损伤比聚丙烯腈碳纤维分别高5.19%和3.70%；在3000℃石墨化处理后,化学惰性较大的中间相沥青碳纤维使界面反应产生的缺陷数量大幅度减小,去除镀层后纤维的损伤比聚丙烯腈碳纤维低1.85%。

Effect of Graphitization Degree of Mesophase Pitch-based Carbon Fibers on Carbon Fiber/Al Interface Damage

Composite of carbon fiber (Cf) with Al-film (Cf/Al) was constructed by magnetron sputtering with mesophase pitch-based carbon fibers of different graphitization degrees as matrix and Al-plate as sputtering target. Then, the microstructure evolution of Cf /Al interface of the prepared composites was investigated, and the damage mechanism of Cf /Al interface was revealed in comparison to that prepared with polyacrylonitrile carbon fiber. The results show: With the increase of graphitization temperature, the size, the degree of orientation and graphitization of graphite micro-crystallites in mesophase asphalt based carbon fiber increased, whilst both of the reaction degree of Cf /Al interface and the damage of carbon fiber reduced. The damage of Cf /Al interface of the composites prepared with Cf of different graphitization degrees depends on the number of initial defects and the propagation of subsequent cracks in the carbon fiber. The graphitization treatment at 2400℃ and 2700℃ could facilitate the crack propagation through graphite micro-lamellas located in between mesophase asphalt-based carbon fibers, however after removing the Al-coating, the fiber damage was 5.19% and 3.70% higher than that of polyacrylonitrile carbon fiber respectively. After graphitization at 3000℃, the mesophase bituminous carbon fiber with higher chemical inertia could reduce the number of defects generated by interfacial reaction, whilst, after removing the Al-coating, the damage of the fiber was 1.85% lower than that of polyacrylonitrile carbon fiber.