Substantial increases in raw material and labor costs have provided the impetus for many diverse investigations aimed at reducing the manufacturing costs of aircraft gas turbine hardware. One of the most significant programs conducted at General Electric during the past decade involves application of powder metallurgy (P/M) processing technology to the fabrication of nickel-base superalloy rotating components. The evolution of P/M technology and its application to a high-strength superalloy, René 95, in a number of diverse aircraft engine components is described. Initial development concentrated on fabrication of P/M hardware by hot isostatic pressing (HIP) cylindrical powder preforms and forging in a conventional die system to an oversize shape. Subsequent refinement of this HIP plus forge process included HIP for shaped preforms followed by forging in an isothermal die system to a near net shape.
Emergence of a second P/M processing technology, designated as-HIP, in which the powder is simply HIP and heat treated, thus eliminating all secondary metalworking operations, is also reviewed. The technical advantages and constraints, along with the projected economic benefits of this new, highly promising P/M process, are analyzed and examples of its application to engine hardware presented. The future of P/M processing in the aircraft engine business, particularly as related to development of advanced superalloy materials, is also discussed.