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Mechanical behaviour of a SiCf/SiC composite for nuclear applications at high temperature
Last modified: 2008-05-22
Abstract
SiC fibre reinforced SiC (SiCf/SiC) composites are among the most interesting materials for high temperature applications. In particular, they are candidate materials for fusion reactors because of the good mechanical properties at high temperature, chemical stability and radiation resistance. This study presents the results of flexural fatigue and flexural creep tests of commercial 2D composite, obtained by chemical vapour infiltration (CVI) of Tyranno fibre preforms and SiC coated by chemical vapour deposition (CVD). The creep behaviour was investigated by means of constant load stress-rupture tests on small-size specimens, in controlled atmosphere at 600 and 1000°C. The fatigue behaviour of the material was studied at room and at high temperature by means of cyclic flexural tests with the peak stress ranging from a small to a significant fraction of the rupture stress. the interaction of creep phenomena and cyclical damage was evaluated. Creep strain analysis, crack growth and fracture surface observations allowed to investigate the mechanisms that affect the crack propagation, the fracture process and the rupture life under cyclic loading and under constant stress loading at different temperatures.
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