Microstructure and Properties of Argon Atomization FGH97 P/M Superalloy

The microstructure, inclusions, prior particle boundary, thermally induced porosity, defects and the tensile properties, stress rupture life, low cycle fatigue of large size disk for a P/M superalloy FGH97, which was made by argon atomization (AA)+hot isostatic pressing (HIP) process, were investigated. The results reveal that the grain size of FGH97 material prepared by AA+HIP+heat treatment is ASTM 8 similar to 9. No continuous network PPB is found, and there is a very small amount of TIP. The size of mostly square gamma' is about 200 nm, and grain boundary gamma' is 1.5 similar to 2 mu m. No coarse gamma' phase and coarse carbides are observed. The average stress rupture time of 650 degrees C/980 MPa is 449 h. The maximum low cycle fatigue life is 258 909 cycles at 650 degrees C, and the average cycle reaches 190 014 cycles. The room temperature, 650, 750 degrees C tensile properties, stress rupture performance at 650 degrees C/980 MPa and the fracture life of low cycle fatigue at 650 degrees C meet the FGH97 alloy technical requirements.