ABSTRACT
There is not much reported work [1-3] on the nano-/micromechanical properties of C/C composites. Usually, the carbon matrix had Young’s modulus at least three times lower than that of the carbon fiber, and the two-dimensional (2-D) C/C composite had Young’s modulus, nearly two to three times lower than those of the three-dimensional (3-D) C/C composites [2, 3]. It is in this context that this chapter focuses on the nanoindentation behavior of the 2-D C/C as well as the C/C-SiC composites using a Berkovich indenter. The relevant processing details of these composites have been given in Chapter 9. We shall evaluate here the nanohardness, Young’s modulus, relative springback, and the relative stiffness of these composites. In addition, we shall try to extract from the experimental data the amount of elastic and plastic energies associated with the nanoindentation processes in these composites. Finally, we shall try to understand how the corresponding microstructural aspects of the composites affect their micromechanical properties. The 2-D C/C composites were prepared with PAN-based woven C-fabric and a graphitic matrix. Some of these were converted to the C/C-SiC composites through the standard LSI method at 1600°C under vacuum [4, 5].
