The characterisation of cracks and voids in two-dimensional carbon-carbon composites

• Published in: Carbon (New York) Vol. 31; no. 1; pp. 103 - 108
• Main Authors: Gao, Fengge, Patrick, John W., Walker, Alan
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1993; Elsevier Science
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Carbon/carbon composites; Ceramic industries; Chemical industry and chemicals; Exact sciences and technology; image analysis; Miscellaneous; Technical ceramics; void structure; image analysis; Carbon/carbon composites; void structure; Pore; Two dimensional structure; Fiber reinforced material; Experimental study; Microstructure; Composite material; Carbon fiber; Crack
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/0008-6223(93)90162-4

From examination of sections by optical and scanning electron microscopy, the voids in two-dimensional (2-D) carbon fibre reinforced carbons (2-D composites) were classified, according to their position, size and orientation, into four groups, namely co-planar, bundle and inter-fibre cracks and interfibre pores. Co-planar and bundle cracks were defined as cracks alligned parallel and perpendicular to the cloth layers, respectively, while inter-fibre cracks and pores were voids, differing in cross-sectional area, present within the fibre bundles. For carbonised preforms, made using PAN-, pitch- and rayon-based carbon-fibre cloths, the four types of void were characterised using image analysis techniques allied to optical microscopy. Wide differences, considered more likely to be associated with prepregging and moulding than with the nature of the fibre cloth, in the voidage present in the carbonised preforms were observed.