Evaluation of Microstructure and Property of a Turbine Blade Made of GH4033 Alloy After Service for 1600h

The microstructure and property degradation of turbine blades in aircraft engines during service would finally pose threat to service safety. But report on systematic research work about microstructure and property degradation of serviced turbine blades is limited. In this paper, the 2^nd stage turbine blade made of wrought Ni-based superalloy GH4033 was taken from an aircraft engine and investigated by metallographic analysis and physical and chemical phase analysis after service exposure for about 1600 engine operating hours (EOH). Microstructural features including grain microstructure, γ+γ' matrix and grain boundary (GB) carbides in different locations of the serviced blade were observed and quantitatively characterized. Vickers hardness and stress rupture tests were also conducted. The microstructure characterization indicates that the degradation in grain size, γ' precipitates and GB carbides is rarely observed in the airfoil. The service temperature is estimated to be lower than 700℃ based on the coarsen of γ' phase. The Vickers hardness and rupture lives of different locations in this blade are similar to those in the shank and met the requirement of Chinese Aeronautical Industry Standard HB/Z 91-1985. Therefore, it is suggested that the service exposure of this blade can be continuously prolonged. This study would be helpful for the evaluation of turbine blade made of wrought superalloys containing low volume fraction of γ' precipitates