The characterization analysis for incompletely recrystallized microstructure of highly-alloyed wrought superalloy GH4065A was carried out.The fatigue tests of standard rodlike specimen and plate specimen have been conducted to compare the fatigue property difference between specimen with homogeneous fine-grained microstructure and specimen with heterogeneous microstructure containing incompletely recrystallized microstructure.The effect mechanism of incompletely recrystallized microstructure on the fatigue property was analyzed.The results show that the residual segregation in the highly-alloyed superalloy that cannot be completely eliminated leads to the presence of incompletely recrystallized microstructure in the corresponding locations between dendrites.The densely precipitated subsize primary y'phase grains make the incompletely recrystallized microstructure have higher strength and resist-ance to the fatigue slippage deformation.Therefore,the expansion of nitride-induced crack and slip band-induced crack are effectively suppressed by the incompletely recrystallized microstructure,and most of the fatigue deformation occurs in the fully recrystallized microstructure.Proper amount of incompletely recrystallized microstructure within the alloy forgings has no significant influence on the fatigue property.
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