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

Abstract

Continuous silicon carbide fiber–reinforced silicon carbide matrix composites (SiCf/SiC) are promising candidate materials for nuclear applications. In this paper, three–dimensional SiCf/SiC composites were fabricated using polymer infiltration and pyrolysis method. Interface properties of SiCf/SiC composites that were irradiated with 3MeV Si ions to 1dpa and 5dpa 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, SiCf/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 SiCf/SiC composite decreases, and full width at half–maximum broadens. TEM micrographs show that ion irradiation damaged the continuity of SiCf/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.