SBIR-STTR Award

The Phase I project will demonstrate the feasibility of producing Mullite (Al6Si2O13) fibers using the Saphikon Edge-defined, Film-fed Growth (EFG) process. The reactivity of mullite melts ranging from 60 to 80 mole percent will be evaluated using crystal growth components fabricated from iridium, and components with a coating of iridium. Fibers will be grown under a range of conditions and evaluated to determine tensile strength at room and elevated (2400 F) temperature. Fiber microstructure will be identified, and comparisons made after extended 2400F exposure in air. Specimen quantities of fiber will be characterized and made available for Air Force evaluation.

Keywords:
Mullite Fibers Composites Ceramics CMC EFG

The Phase II project will determine the best process parameters for the growth of Mullite (Al6Si2O13) single crystal fibers using the Edge-defined, Film-fed, Growth (EFG) process. Included in this investigation will be melt chemistry, die type, growth rate and melt temperature. Die fabrication and materials issues will be investigated to provide improved dies and hot zone parts and provide for a significant scale-up in process capability. The multi-fiber growth of mullite fibers will also be demonstrated with a deliverable goal of 1000 meters. A 50-75 micron mullite fiber will be demonstrated. The fiber grown will be characterized using metallography, room and elevated temperature tensile strength, creep and static fatigue.