Interface Structures of the Functional Bonded Materials Using Nanocrystalline Carbon 60

利用高分辨电子显微镜研究了纳米晶碳60的晶界原子结构，以及严重变形的碳纳米管和纳米管纤维增强的纳米晶碳60的缺陷结构，并研究了它们对力学性能的影响，作为开发新型工程材料的一部分。碳60因其高度对称的晶体结构而具有独特的力学性能。具有许多滑移面的面心立方结构允许晶体大量变形。滑移迹的立体分析表明，在室温下活性体系为{ll} <110>。为了提高碳60的延展性，采用10torr的氦汽化法制备了纳米晶团聚体。室温拉伸试验结果表明，纳米晶试样具有较好的韧性，加工硬化率与单晶C60相当或低于单晶C60。结果表明，在室温条件下，细晶聚集体的超塑性行为仍然存在。另一方面，饭岛发现的碳纳米管是圆柱形的高阶富勒烯，在C60生产过程中作为双产物生长在阳极的碎屑中。它是一种晶须，因此通常期望具有极高的抗拉强度和零塑性。然而，我们的实验证明了纳米管的变形。观察到弯曲的纳米管，但没有发现断裂的例子。高分辨电镜观察表明，纳米管的变形为内压缩侧屈曲。碳纳米管的工程可以继续进行，因为这种材料已被证明具有延展性。有人建议用纳米管作为纤维增强C60或软金属。碳纳米管/C60体系可以通过简单的挤压代替。在复合材料中，纳米管的排列是通过在银鞘中挤压复合材料来实现的。高分辨电子显微镜显示，碳纳米管在挤压复合材料中是无缺陷的。然而，基体C60是纳米晶，在室温下具有良好的延展性。少

Atomic structures of grain boundaries in nanocrystalline carbon 60, and defect structuers in heavily deformed carbon nanotube as well as nanotube fiber reinforced nanocrystalline carbon 60 were examined by high resolution electron microscopy and their influence on the mechanical properties were investigated as part of our efforts to develop the new carbons as engineering materials. The carbon 60 is unique in the mechanical property due to highly symmetrical crystal structure. Face centered cubic structure with many slip planes allow the crystal to deform by a large amount. A stereographic analysis of the slip traces showed that the active system at room temperature is {lll} <110>. In order to increase the ductility of carbon 60, the nanocrystalline aggregate was produced by vaporization in Helium at 10 Torr. The results of the tensile tests of thin sheet specimen at room temperature, the nanocrystalline specimen was most ductile and the work hardening rate comparable or below that of s … More ingle crystalline C60. The result suggested that superplastic behavior of fine crystalline aggregate operates even at room temperature in C60.On the other hand, carbon nanotube, discovered by Iijima is cylindrical high order fullerene which grows in the debris on the anode as a biproduct during production of C60. It is a kind of whisker, so taht an extremely high tensile strength and zero plasticity is generally anticipated. However, our experiment proved the defomation of nanotubes. Curved nanotubes were observed, while no example of fracture was obrained. High resolution electron microscopy showed that the deformation is buckling of inner compressive side of the nanotube.The engineering of the carbon nanotube can proceed because the material has been proved ductile. The use of nanotube as the fiber to strengthen C60 or soft metals has been suggested. The carbon nanotube/C60 system can be produced simply by extrusion instead. The composite where the alignment of nanotube is achieved by the extrusion of the composite in a silver sheath. High resolution electron micrograph showed that the carbon nanotubes are defect free in the as extruded composite. The matrix C60, however, was nanocrystalline suggesting a good ductility at room temperature. Less