Changes of microstructure and mechanical properties of Hi-Nicalon Type-S SiC composites irradiated to 100 dpa

Ozawa, Kazumi; Koyanagi, Takaaki*; Nozawa, Takashi; Kato, Yutai*; Kondo, Sosuke*; Tanigawa, Hiroyasu; Snead, L. L.*

A silicon carbide fiber-reinforced silicon carbide matrix (SiC/SiC) composite is a promising candidate material for an advanced fusion DEMO blanket. High-dose irradiation experiments were performed with our special focuses on understanding; (1) integrity of the Hi-Nicalon Type-S (HNLS) composites, (2) functionality of thin pyrocarbon (PyC) /SiC multilayer, and (3) clarifying the mechanism underlying degradation, as feedback to R&D on SiC/SiC composites. The materials used in this study were plain-weave HNLS composites produced via the chemical vapor infiltration process. Neutron irradiation was conducted in the HFIR at ORNL. The peak neutron fluence was ~1.010 n/m (E 0.1 MeV, equivalent to ~100 dpa) at nominal irradiation temperatures of 300, 500, and 800C. Results of post irradiation experiments including 1/4-four-point flexural tests, SEM, and TEM observation were reported.