Fabrication of Composite Turbine Powershafts by Explosive Welding Techniques

There is increasing demand to reduce the overall weight and increase the efficiency of aircraft turbine engines through the use of light weight, high strength composite structures incorporating metal matrix composites (MMCs). One of the major, critical components offering siginificant potential for such weight savings with titanium alloy based MMCs is the main powershaft of the engine. A major difficulty with such MMC type components is making reliable couplings such as splines or joints such as welds with other mating components. The objectives of the proposed program is to demonstrate the technical and manufacturing process feasibility for using the explosive welding process to fabricate high quality, high integrity transition joints between the MMC and steel alloy or nickel base alloy wear resistant sections of a composite shaft. The project will initially involve selecting candidate MMC/metal alloy combinations in transition joint configurations for preliminary screening tests and weld joint property data generation in the Phase I explosive welding studies. Based on the testing and analysis of the results of these studies, the optimum materials combination and joint configuration will be selected for establishing the manufacturing methodology and fabricating prototype test shafts in the Phase II portion of the program. Anticipated Benefits: The development of this advanced joining approach for fabricating light weight, high performance composite aircraft turbine powershafts containing metal matrix composites has the propulsion/power systems and being broadly applicable in both military and commercial sectors.