Abstract: A dual alloy cooled turbine is manufactured by casting a hollow cylinder of first nickel-base alloy material with high creep resistance to produce directionally oriented grain boundaries. A preform of a second nickel-base alloy material with high tensile strength and high low-cycle-fatigue strength is diffusion bonded into the bore of the hollow cylinder by subjecting the cylinder and preform to hot isostatic pressing. The resulting cylindrical block is cut into thin precisely flat wafers. A plurality of alignable holes for forming fluid cooling passages are photochemically etched into the individual wafers. The wafers then are laminated by vacuum diffusion bonding techniques, with the holes aligned to form fluid cooling passages. The resulting laminated block is machined to produce the turbine wheel with turbine blades through which the cooling passages extend.

Abstract: A dual alloy turbine wheel manufacture of a cast integral blade ring pressure-sealed to a wrought alloy hub and thereafter bonded thereto by hot isostatic pressing.