Influence of Anisotropy of Pyrolytic Carbon on Effective Properties of Carbon/carbon Composites

This paper deals with the micromechanical modeling of carbon/carbon composites (C/C) fabricated by chemical vapor infiltration (CVI) of carbon fiber pre-form. The technology of CVI involves synthesis of pyrolytic carbon (PyroC) particles from hydrocarbon gas and their deposition on carbon fibers. The process results in formation of a porous pyrolytic carbon matrix filling space between the fibers. This matrix is organized in the cylindrically orthotropic layers concentrically located around fibers as shown in Fig. 1a. These layers correspond to different degrees of preferred orientation (or texture) of basal planes in PyroC that can be characterized by the degree of optical anisotropy in polarized light microscopy, see [1] and references therein. The number of layers, their width, order and structure are strongly influenced by the parameters of infiltration, such as temperature, pressure, residence time, etc.