Thermomechanical Behaviour of 2D-SiC/Sic Composites with Nanoscale-Multilayered (PyC/SiC) n Interphases

2D woven SiC/SiC composites, with nanoscale-multilayered (PyC/SiC) n interphases, have been made via chemical vapour infiltration of a preform of either Nicalon or Hi-Nicalon fibres. The nanoscale-multilayered (PyC/SiC) n interphases consist of n successive PyC-SiC sequences. In the present paper n = 10 and the thickness of the PyC and SiC sublayers was about 20 nm and 50 nm respectively. The influence of Hi-Nicalon fibres and multilayered interphases on the mechanical behaviour at room temperature and the lifetime in cyclic fatigue at 600°C and 1200°C was investigated. The Hi-Nicalon fibre and the multilayered interphases are shown to lead to improved 2D-SiC/SiC composites.