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A manufacturing process for dual-structured turbine disks made from PM nickel-base superalloys has been specially developed. The disks are composed of two metals: AF115, which has superior stress rupture properties, was used in the rim region, and TMP-3, which has good tensile properties and a low cycle-fatigue life, was used in the bore region. A 400mm diameter dual-property disk was successfully produced through double-stepped HIP treatment and superplastic forging, in which gas atomized powders composed of the above alloys were consolidated into a well-designed preformed structure. After heat treatment, the microstructure of the product was very fine and homogeneous in the bore region, and coarse grains were obtained in the rim region. The mechanical properties were of such high quality as to enable practical use as a turbine disk.

High-pressured water atomization is a viable production method for fine metal powders used for metal injection moulding and for additives in sintered parts. The atomization mechanism using two types of water jet nozzle (Cone and V-jet nozzle) under high pressure up to 70MPa was studied. The pulverizing capability under high-pressured water atomization strongly depends on a gas stream induced by the ejecting effect of water jets, which surround the melt stream. A mean particle diameter of less than 10 μm can be obtained by the V-jet nozzle.