Progress in ceramic and intermetallic high-temperature composites is limited by the currently available ceramic fibers. Single-crystal oxide fibers have superior microstructure, high melting points, high strength and modulus, low creep at high temperature, and resistance to oxidation. Recently, there has been considerable interest in mullite (3Al2O3-2SiO2) as an enabling propulsion material because it has good high-temperature strength and resistance to creep properties. Although it is a single-crystal, continuous mullite fiber is very difficult to grow due to incongruent melting and a range of solid solution. An innovative approach, using edge-defined film growth or Stepanov growth methods, should be feasible for processing single crystal mullite fiber. These technologies will be investigated and developed to produce initial quantities of fiber for NASA.
Potential Commercial Applications:Applications include reinforcement of intermetallic and ceramic matrix composites used for advanced turbine engine hardware, e.g., high speed civil transport.
