Ceramic fiber-reinforced composites are expected to be potential candidates as fusion reactor structural materials. Aluminum matrix composites reinforced with carbon (C) or silicon-carbon (SiC) fibers are investigated. The objectives of this investigation are to evaluate the potential of aluminum (Al) matrix composites as low-activation fusion reactor materials and to develop them for fusion applications.
Mechanical properties were measured by the three point bending test, the mini-size specimen tension test for composite materials, and the monofilament tension test. Microstructure was inspected by means of SEM (scanning electron microscope) and TEM (transmission electron microscope). The effects of radiation were studied using fission neutrons from JOYO (FBR) (Japanese fast breeder reactor) and JMTR (BWR) (Japanese materials testing reactor) and 1-MeV electrons in HVEM (high voltage electron microscope). Al matrix composites showed excellent stability under irradiation up to a certain fluence, termed the threshold fluence. For SiC fibers in the composites, increases in tensile strength and Young's modulus as well as crystallization of amorphous SiC were observed below the threshold fluence. But above the threshold fluence, strength drastically dropped. The alloying of nickel and silicon to aluminum matrix alloys is suggested to be unfavorable for SiC/Al composite materials used in a fusion environment.