Microstructure evolution and processing maps of GH4169 during deformation

The single-pass isothermal compression tests on a Gleeble−3500D simulated machine was carried out in this work to study the dynamic recrystallization behavior of GH4169 alloy in the temperature ranging from 900 ℃ to 1150 ℃ and strain rate ranging from 0.01 s⁻¹ to 10 s⁻¹ and the deformation degree ranging from 10% to 70%. Complete recrystallization condition of the alloy at a variety of different deformation conditions were identified, and recrystallization maps were plotted. Thermal processing maps of the alloy were also proposed. The results show that the recrystallization fraction of GH4169 alloy increases with the increase of deformation temperature. The larger the deformation and the slower the strain rate, the wider the temperature range of fully dynamic recrystallization; When the strain rate is 0.01 s⁻¹, the whole process of deformation- recovery- recrystallization-grain growth occurs. When the strain rate is 10 s⁻¹, only the process of deformation- recovery-(complete/partial) recrystallization occurs, and there is no sufficient dynamic condition for grain growth. With the increase of deformation ratio, the easy processing range (η) and stable processing range (ξ$ \left(\dot{\mathrm{\varepsilon }}\right) $) of GH4169 alloy are wider. When the deformation ratio is 70%, the temperature is 965 ~ 1134 ℃, and the strain rate in the range of 0.02 ~ 10 s⁻¹, (ξ$ \left(\dot{\mathrm{\varepsilon }}\right) $) value is greater than 0 which indicates in the processing stable zone.