MELT EXTRACTION OF OXIDE FIBER REINFORCEMENTS FOR HIGH TEMPERATURE INTERMETALLIC COMPOSITES

This work will seek to demonstrate the melt extraction process for the formation of a continuous oxide fiber reinforecement for intermetallic composites. Alumina-YAG eutectic, which has demonstrated chemical resistance in TiAl, has an attractively high coefficient of thermal expansion (CTE), good fracture toughness and creep resistance, has not been produced by melt extraction. Building on experience in melt extraction of alumina the conditions required for formation of continuous lengths of fiber by an optimum heating method will be determined. Fiber will be characterized by optical and electron microscopy, metallography, and mechanical tests for tensile strength and modulus. Heat treatments will be performed to develop useful microstructures. The fiber properties will be correlated with processing parameters to recommend an approach for further investigation.