GH4033涡轮叶片服役1600h后的显微组织及力学性能评价

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

航空发动机涡轮叶片服役过程中将产生组织退化和性能降低,从而威胁其服役安全。已有研究中,对长时服役后的叶片组织退化和性能损伤的评价研究较少。本研究对服役1600h后的GH4033合金二级涡轮叶片进行金相解剖分析和物理化学相分析;同时观察并量化表征该二级涡轮叶片各部位晶粒组织,γ+γ′基体组织和晶界碳化物,测量不同部位的维氏硬度和持久性能,分析其组织退化与性能损伤规律。结果表明:服役后叶片各部位组织退化及性能损伤程度不明显,根据γ′相的量化表征结果推断该叶片最高服役温度应不高于700℃。叶身各部位持久性能及维氏硬度与榫头部位相当,均符合航空工业标准HB/Z 91—1985要求,因而判断该叶片仍可以继续使用。研究结果对低γ′相体积分数的变形高温合金航空发动机涡轮叶片的服役安全评价具有指导意义。

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 2nd 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 than700℃ based on the coarsen ofγ′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 ofγ′precipitates.