Mechanical and thermal properties of SiCf/SiC composites irradiated with neutrons at high temperatures

A high fluence irradiation of SiCf/SiC composites has been performed to study the effect of neutron irradiation on the mechanical and physical behaviour of those composites. The fibre reinforced silicon carbide composites have been irradiated at two temperature levels of 600 °C and 900 °C up to a fluence of 3.5 × 1025 n/m2 (E > 0.1 MeV). The stiffness of the bending bars after irradiation changed with factors between 0.75 and 1.04 for the different composites while the bending strength after irradiation was reduced with a factor of 2 in some cases. The laser flash thermal diffusivity ratioʹs (αirr/αo) of the composites measured at 600 °C are from 0.1 to 0.5 and from 0.25 to 0.75 for an irradiation temperature of 600 °C and 900 °C, respectively. The dimensional changes observed are small.