Comparison of the mechanical behaviour of SiCf/SiC composites following neutron irradiation and helium implantation

Thermomechanical behaviour of 2D-SiCf/SiC composites following neutron irradiation and helium implantation was studied. Three-point bending tests were carried out at room temperature (RT) and 1073 K, after neutron irradiation (1.29, 2.69 and 5.23 dpa) at the high flux reactor-Petten. Results of RT mechanical tests on helium implanted bars are also referred and discussed. The samples with an accumulated damage dose of 1.29 dpa show a strength decrease and improved bend toughness. For the higher neutron fluences the composite exhibits a brittle behaviour. For helium implanted materials, a strength decrease comparable to that observed for those neutron irradiated at lower fluence is present, but its toughness is reduced. (orig.)