GROWTH OF SPINEL SINGLE-CRYSTAL FIBERS BY THE LASER-HEATED FLOATING-ZONE TECHNIQUE AND THEIR CHARACTERIZATION AS HIGH-TEMPERATURE REINFORCEMENTS

Single crystal MgAl2O4 fibers were grown by the laser-heated floating-zone process, and were evaluated as reinforcements for high temperature composites. Composition, growth axis, and atmospheres were varied to determine their effects on defects and high temperature properties. Fibers were characterized topographically, microstructurally, crystallographically and mechanically, at room temperature as well as at elevated temperatures. Elevated temperature strengths and creep rates of [110] MgAl2O, fibers equalled or exceeded those exhibited by highly optimized c-axis sapphire fibers.