Effect of dual-beam-irradiation by helium and carbon ions on microstructure development of SiC/SiC composites

Microstructural changes of SiC-fiber reinforced SiC-matrix (SiCf/SiC) composites after simultaneous helium-ion and carbon-ion irradiations were studied. SiCf/SiC composite specimens were irradiated up to 10 dpa and 1000 at. ppm He at 1073 and 1223 K. Cross-sectional microstructural observation and irradiated surface analyses were performed. Dimensional changes in SiC-fibers and pyrolytic graphite layers were observed but a dimensional change was not observed in the SiC-matrix. Microstructural features such as voids and dislocation loops were not observed in these experimental conditions.