Fabrication of SiCf/SiC and integrated assemblies for nuclear reactor applications

Abstract

This study examined the processing feasibility of electrophoretic deposition (EPD), as an effective matrix infiltration method, in conjunction with hot-pressing to fabricate dense and tough SiCf/SiC materials. Flat and tubular specimens were fabricated by hot pressing at 1750°C and 20MPa after infiltrating a SiC-based matrix phase into Tyranno® SA3 SiC fabrics, which can be used as the core structural components for the next generation fission reactors and as blanket materials for future fusion reactors. For the tubular specimens, two types of preforms were compared: filament wound and jelly-rolled with different woven structures. The incorporation of SiC green tapes between the successive layers of SiC fabrics allowed better control over the composite density and pore distribution. The macro-architecture of the composites was optimized in terms of the slurry composition, sintering additives, and phase evolution. Fractography revealed considerable debonding at the SiCfiber-PyCcoating interface and fiber pull-out with pronounced tail extension behavior when tested in flexure. Joining of the flat-tube and flat-flat SiCf/SiC was performed using a range of filler systems; the structures integrated using the Ti-based MAX fillers at 1750°C and 3.5MPa for 1–2h soaking time are discussed.