In-phase thermal-mechanical fatigue investigation on hollow single crystal turbine blades

Thermal-mechanical fatigue (TMF) is the primary cause of failure of nickel-based single crystal turbine blades. TMF experiments have been performed on the critical section which is subjected to the most serious damage and determined by numerical calculation combined with service failure experience. An experimental system including the loading, heating, air cooling, water cooling, and control subsystems, is constructed to satisfy the TMF experimental requirements. This experimental system can simulate the stress field, temperature field, air cooling process, and TMF spectrum on the critical section under service conditions in a laboratory environment. A metal loading device and a new induction coil are developed to achieve the required stress and temperature distributions on the critical section, respectively. TMF experimental results have indicated that cracks initiated at the trailing edge of the suction surface on the critical section. Based on these experiments, life prediction and failure analysis of hollow single crystal turbine blades can be investigated.