Fatigue properties of GH4169 and GH4586 superalloys at 800 ℃
In order to provide a basis for the safe use of GH4169 and GH4586 nickel based superalloys which widely used in various components of aerospace engines in China under harsh service conditions,the fatigue properties of the two alloys at 800 ℃ was tested using a high-frequency fatigue testing machine and S-N curves were drawn.The fatigue fracture morphology of the two alloys was observed using scanning electron microscopy,and the fatigue fracture characteristics of the two alloys at 800 ℃ were analyzed by microstructure observation.The results show that at 800 ℃,the needle-like δ phase with large aspect ratio in the GH4169 alloy induces stress concentration,which affects its fatigue properties,and the inhibition of creep by the stable granular TiN at the grain boundaries of the GH4586 alloy and its combination with the second phase strengthening effect of TiN particles and fine carbides are the main reasons for the superior fatigue properties of the GH4586 alloy.The average fatigue strength limits of the GH4169 and GH4586 alloys at 800 ℃ are 363.33 and 490.00 MPa,respectively.
GH4169 alloyGH4586 alloyhigh temperature fatigue propertygrain boundary phase
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