PNNL

Abstract

SiC is an excellent material for fusion reactor environments, including first wall plasma facing materials and breeder-blanket modules. In the form of woven or braided composites with high-strength SiC fibers it has the requisite mechanical, thermal, and electrical properties to be a useful and versatile material system for fusion applications [1-7]. The use of SiC-reinforced composites for fusion reactors or other nuclear applications will not be restricted to 0/90 aligned fiber architecture in all cases. It is important to understand the role of fiber orientation in the strength, toughness, and time-dependent properties for such materials. The use of high-strength ceramic fibers for composites is predicated on optimizing the strength, fracture resistance, and retained strength in aggressive environments, which argues for the best use of fiber strengths, namely on-axis loading for full load transfer to the high-strength fibers. Relatively few researchers have systematically studied the effects of fiber orientation on composite properties [8-10], and none have, to the best of our knowledge, performed any time-dependent testing of composites with off-axis or inclined fiber orientations.