Forging process of a new type high-performance P/M turbine disk superalloy

Abstract

The hot forging deformation experiments of a new type high performance powder metallurgy (P/M) turbine disk superalloy FGH98 I has been performed under the conditions of the deformation temperatures of 1050-1100°C and strain rates of 0.0003∼0.01 s-1, and then with subsequent subsolvus and supersolvus heat treatments for 0.25-1h. The results show that FGH98 I alloy exhibits the desired thermoplastic response under the testing conditions. The forging flow stress increases with increasing strain rate and decreasing temperature. The mean grain size of as-forged FGH98 I varies between 6.0μm and 8.0μm, and only slightly coarsens with the increasing temperature and decreasing strain rate. The mean grain size of the subsolvus heat treated specimens varies between 8.6μm and 24μm, slowly coarsens with increasing solution time, and moderately coarsens with increasing temperature and decreasing strain rate. The mean grain size under supersolvus heat treated varies between 10μm and 46μm, obviously coarsens with increasing temperature and solution time, and coarsens with decreasing strain rate. The above results can be used for optimizing the practical forging process of FGH98 I disk alloy.