Effects of silicon ion irradiation on the interface properties of SiCf/SiC composites

Abstract Continuous silicon carbide fiber–reinforced silicon carbide matrix composites (SiC f /SiC) are promising candidate materials for nuclear applications. In this paper, three–dimensional SiC f /SiC composites were fabricated using polymer infiltration and pyrolysis method. Interface properties of SiC f /SiC composites that were irradiated with 3 MeV Si ions to 1 dpa and 5 dpa at room temperature were studied using single-fiber push–out test, Raman spectroscopy, and transmission electron microscopy. Results indicate that, after being irradiated with different doses of Si ions, SiC f /SiC composites have weaker interfacial shear strength compared to that of samples before irradiation. The greater that the ion irradiation damage is, the lower that the interfacial shear strength is. With an increase in ion irradiation dose, the strength of the disordered (D) and graphitic (G) characteristic peaks in Raman spectra of SiC f /SiC composite decreases, and full width at half–maximum broadens. TEM micrographs show that ion irradiation damaged the continuity of SiC f /SiC composites, and microcracks appeared at pyrocarbon interface between the fiber and matrix. The crystallinity of SiC was lowered, the grain size shrank, and the ordered C phase became amorphous noncrystalline structure.