Irradiation effects on thermal expansion of SiC/SiC composite materials

Irradiation-induced dimensional change and thermal expansion of two kinds of composites, self-particle reinforced SiCp/SiC composites and a Hi-Nicalon™ SiC fiber reinforced SiCf/SiC composite, and monolithic α-SiC were measured after irradiation at 0.2 dpa with irradiation temperatures of 573, 673 and 843 K using the JMTR. From the measurement, swelling was observed for the SiCp/SiC composites and the monolithic α-SiC, on the contrary, the SiCf/SiC composites showed a shrinkage. The measured thermal expansion increased with increasing the specimen temperature below the irradiation temperature, and then rapidly decreased over the irradiation temperature. The so-called ‘temperature monitor effect’ of the silicon carbide was clearly observed for all specimens, the monolithic α-SiC and both composites.