Development of a Ceramic Blade-Superalloy Disk Attachment For Gas Turbine Rotors

With improving ceramic materials and fabrication techniques, a major effort is underway to design and test ceramic hot flow path components for gas turbine engines. The most critical and furthest from a satisfactory engineering solution is the turbine rotor. This paper summarizes the development of a new technique for attaching hot pressed silicon nitride ceramic airfoil shapes to a wrought AF2-1DA superalloy disk using the GATORIZING™ isothermal forging process. Attachment design, fabrication and testing techniques are discussed leading to the establishment of a 99.5 percent statistical lower bound P/A blade stress of 20.5 ksi (141 MN/m²). Subsequent elevated temperature attachment development techniques for establishing design criteria for operation in the gas turbine environment are also defined.