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Volume 19, Issue 2, 2010
LETTER:TENSILE BEHAVIOUR AND DAMAGE EVOLUTION OF A C/SiC
MINICOMPOSITE FABRICATED BY CHEMICAL VAPOUR INFILTRATION
Yiqiang Wang1,2,*, Litong Zhang2
1 College of Aeronautical Engineering, Civil Aviation University of China, Tianjin 300300, People’s Republic of China
2National Key Laboratory of Thermostructure Composite Materials, Northwestern Polytechnical University, Xi’an Shaanxi, People’s Republic of China
* Author to whom correspondence should be addressed, e-mail: wyq80@yahoo.com.cn
Received 10 November 2009; accepted 9 March 2010
ABSTRACT
The tensile behaviour of a C/SiC minicomposite fabricated by chemical vapour infiltration was examined and the associated damage evolution was monitored by using acoustic emission (AE) technique. The microstruc¬ture of minicomposite can be characterized by a uniformly thick SiC sheath, the thin fibre coatings, and large pores due to the tendency of fibres to cluster in the minicomposite. The load-displacement curves of minicom¬posite show a greatly nonlinear behaviour with four distinct regimes: initial self-alignment due to relaxation of fibres followed by preexisting microcrack extension, matrix macrocrack multiplication and then saturation. All these regimes can be well characterized by the corresponding AE activities. Therefore, it is believed that such experimental results would be beneficial to the optimization of processing conditions and derivation of parameters necessary for further modelling of the thermomechanical behaviours of real C/SiC composites with more complex architectures by fabricating minicomposites in a short time.
KEYWORDS:Ceramic matrix composites; tension test; acoustic methods; chemical vapour infiltration
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