Hybrid Impeller Disk for High Pressure Compressor Configurations in Future Turboshaft Engines

Keystone Synergistic Enterprises, Inc. proposes to use induction heating to create a hot zone in the rim of radial impellers so that the rim of the rotors will be preferentially heated above the gamma prime solvus. This will cause the formation of a dual property microstructure in the impeller. A fine grain size, established by either the forging temperature will be maintained in the hub of the rotor. Coarse grains, resistant to creep loading will be grown on the rim. The direct induction heating approach is novel. It will use a current concentrator to establish a carefully controlled heating zone within the rim. The transition between the fine grain size and coarse grain size will be defined by OEM subcontractors Rolls-Royce and Honeywell Aerospace. Induction heating has been selected because it: • Is Low cost • Exhibits Controlled heat up rates • Is Easily automated • Produces controlled thermal profiles Keystone will provide a shaped induction coil which will induce a controlled hot zone in the Alloy 10 or RR1000 impeller. Work on coil fabrication will begin early in the optional phase. Keystone will work with the OEMs to design the shape of the heat treat preform.