某燃气轮机涡轮叶片长期服役后的微观组织与性能

Microstructure and properties of a gas turbine blade after long-term service

研究了服役45000 h后的燃气轮机叶片不同部位微观组织与持久性能的退化行为。试验结果表明:长时服役后,叶片榫齿部位的微观组织未发生明显的退化损伤,叶片叶尖部位的微观组织则发生明显的退化,其中MC型碳化物发生退化分解,立方状γ′相退化成粗大的球状γ′相。长时服役后,叶片的硬度没有发生明显的变化,而蠕变持久性能明显降低,该燃气轮机叶片在850℃下10^(5) h的外推持久强度降低至66.72 MPa。

Microstructure and creep rupture property of a gas turbine blade at different positions after 45000 h cumulative operation were researched.The experimental results show that the microstructure of the tenon tooth blade has no obvious degradation,however,the microstructure degrades obviously for the leading edge on the section near blade tip,in which the MC-type carbides are degraded and decomposed,and the cubic γ′phase degenerates into coarse spherical γ′ phase.After long-term service,the blade hardness has no obvious change,however,the creep rupture strength reduces obviously and the extrapolation rupture strength of the gas turbine blade at 850 ℃ for 10^(5) h reduces to 66.72 MPa.