Dec 4, 2009

Air Force award Reactive Fusion Welding for UltraHigh Temperature Ceramic Composite Joining

For this Phase I program, MO-SCI Corporation and Missouri University of Science and Technology (Missouri S&T) will develop reactive fusion and reactive plasma welding techniques that are capable of joining ultra-high temperature ceramic (UHTC) composites. Past work at Missouri S&T demonstrated the feasibility of fusion welded UHTC composites. This program will build on the joining successes at Missouri S&T through development of reactive and non-reactive filler materials that are needed to improve weld joint quality. Preheat temperature, power input, filler type, filler introduction rate, and cooling rate will be studied to generate a list of critical process variables that affect the quality of fusion welded joints between UHTC composites. Size and geometry restrictions of 2 welding processes will be assessed to better understand the applicability to the manufacture and repair of integrated TPS. The collaborative efforts will 1) demonstrate the feasibility of low porosity fusion welded UHTC joints, 2) measure the ambient and high temperature mechanical properties for three joint geometries, and 3) quantify the effects of the proposed fusion joining processes on the thermal conductivity of the joints. Joints with predictable thermal and mechanical behavior will be produced at the conclusion of this research and joining of these welded UHTC composites to high temperature metallic alloys will be demonstrated.