论文部分内容阅读
利用催化化学气相沉积工艺在炭纤维(Cf)表面原位生长碳纳米管(CNT),经聚合物浸渍-热解(PIP)致密化后制备了CNT强化的Cf/Si C复合材料.结合微米压痕和纳米压痕测试方法在微米、纳米尺度研究了CNT强化的Cf/SiC复合材料界面、微区基体以及纤维-CNT-基体组元区域的力学响应机制.结果表明,CNT生长点具有较高的结合强度,界面脱黏出现在纤维/热解碳界面处,原位生长的CNT显著强化了纤维-基体界面结合强度.PIP工艺对CNT造成损伤,致使CNT强化的微区基体的模量和硬度下降,而CNT的拔出、裂纹桥连等行为阻碍了微区基体的裂纹扩展,进而提高了微区基体的破坏容忍度.理论计算结果显示,由CNT带来的韧性贡献约为310.8 J/m2.界面强化效应和微区基体裂纹扩展阻碍效应使纤维-CNT-基体组元的抗损伤能力得到了提高.利用微纳米测试连用手段可深入了解多级增强复合材料的纳米效应.此外,理论计算表明,CNT/基体的界面修饰及对CNT的有效保护会进一步提高CNT对微区基体的韧化效果.
Carbon nanotubes (CNTs) were grown in situ on the surface of carbon fiber (Cf) by catalytic chemical vapor deposition (CVD), and CNT-reinforced Cf / SiC composites were prepared by polymer impregnation-pyrolysis (PIP) Indentation and Nanoindentation Tests The mechanical response of the CNT-reinforced Cf / SiC composite interface, the micro-zone matrix and the fiber-CNT-matrix elemental area was investigated at the micro and nano-scale.The results show that the CNT growth point High bond strength and interface debonding appear at the fiber / pyrolytic carbon interface, and CNTs grown in situ significantly strengthen the bond strength of the fiber-matrix interface. The PIP process damages the CNTs, resulting in that the modulus of the CNT- And the hardness decreases, while the pulling-out of CNTs and the bridging of cracks prevent the crack propagation in the micro-zone matrix and thus improve the failure tolerance of the micro-zone matrix. Theoretical calculations show that the toughness contributed by CNT contributes about 310.8 J / m2. The interfacial strengthening effect and the crack growth inhibiting effect of the micro-matrix enhance the anti-damage ability of the fiber-CNT-matrix elements. The micro-nano test can be used to understand the nano effect of multi-stage reinforced composites In addition, theoretical calculations show that CNT / matrix interfacial modification and effective protection of CNTs can further improve the toughening effect of CNT on the micro zone matrix.