Superpiastic isothermal forging process called Gatorizing has been developed for manufacturing of turbine discs of nickel-base superalloy IN-100. A key point of this technology is a preform processing aimed at grain refinement for superplasticity but no details have been made public. Therefore, powder-consolidated Mod. IN-100 samples made by a hot isostatic pressing were extruded at various reductions and temperatures. The optimum conditions required to obtain the fine grained sound sample and

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... he recrystallization behaviour during extrusion and subsequent annealing were investigated. It was shown from results that (1) the reduction should exceed about 70% and ( 2 ) the temperature range should be 1 353-1 393 K, strictly speaking ,1 393 K was most desirable. Furthermore, it was discussed whether a tensile strength and an elongation at 1 033 K of greater than 1 568 MPa and 20% which were aimed at by "the R &D Project of Basic Technology for Future Industries" sponsered by Agency of Industrial Science and Technology ,MITI, were possible or not to be achieved by a optimum work processing, for a traditional alloy.