Microstructures and mechanical properties of DZ125 directional solidified superalloy repaired by HIP technology

DZ125 directional solidified superalloys show excellent bearing temperature ability and creep resistance and have been widely used to manufacture the advanced aviation engine blades parts. However, the high temperatures and stresses for longtime service would cause a loss of mechanical properties and service life. In this paper, the damaged alloys were repaired using hot isostatic pressing combined with rejuvenation heat treatment technology, where the irregular γ′ phases in damaged alloys are recovered to be cubic particles like original state and the creep cavities and casting porosities also reduce obviously compared with those in damaged state. The restorable alloys exhibit apparently higher tensile properties and hardness than the alloys in damaged state, which is close or even more than those of original alloy, and their elongation and rupture life can satisfy criterion completely. This method can be easily extent to repair other damaged superalloys.