Direct measurement of crack-bridging tractions: A new approach to the fracture behaviour of ceramic/ceramic composites

• Published in: Composites science and technology 1996-01, Vol.56 (7), p.817-823
• Main Authors: Brenet, P., Conchin, F., Fantozzi, G., Reynaud, P., Rouby, D., Tallaron, C.
• Format: Article
• Language: English
• Subjects: Applied sciences; brittle matrix; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; composites; Exact sciences and technology; fracture; Glass-ceramics; Glasses; interface; p( u) curve; pull-out; Structural ceramics; Technical ceramics
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/0266-3538(96)00026-7

By comparison with bulk ceramics, ceramic-matrix composites exhibit large toughening as a consequence, initially, of matrix crack bridging by intact fibres and then by broken fibres undergoing pull-out. A method for the direct measurement in double-edge-notched specimens of the bridging tractions, p, as a function of crack opening displacement, u, is presented. The p(u) curve shows a peak which corresponds to instability of the bundle of bridging fibres. The tail of the curve is linked to the fibre pull-out process and gives access to the average pull-out length and to the interfacial sliding strength. Finally, the crack-growth resistance induced by the bridging phenomenon can be estimated from the integral of the p(u) curve. Two materials are used in this study: a woven 2D SiC SiC composite processed by SEP, France, and a laminated [ 0 90 ] SiC MAS-L composite processed by Aérospatiale, France. Results of p(u) curve analysis are given and discussed.