Development of rejuvenation process for creep damage of turbine blades

Extending the service life of turbine blades is a crucial problem that needs to be solved in aero engines. The rejuvenation technology of service damages works as an important means to guarantee the long-time, high-reliability and low-cost operation of engines. A review of the state of the art in the life-extending technologies for the creep damage of in-service turbine blades is presented. The progress of the life-extending technologies, from simple heat treatment to rejuvenation heat treatment and hot isostatic pressing (HIP) rejuvenation, is analyzed based on their characteristics. General principles on the recovery of creep damage and advantages of the HIP rejuvenation technology are pointed out. The healing mechanism of creep cavities under HIP conditions is highlighted and elaborated, and several important cavity sintering models are introduced. Some problems and challenges of the current life-extending technologies are presented, and the prospective research directions for HIP rejuvenation in China are proposed.