Effect of cold rolling deformation and heat treatment on microstructure and hardness of GH4169 alloy plate

Cold rolling and heat treatment experiments of GH4169 alloy with different deformation were carried out. Effect of different cold rolling deformation and heat treatment state on microstructure and hardness of plate was analyzed. Cold rolling experimental results show that dislocation density is increased, dislocations are cross slipped, deformation texture are enhanced, twins boundaries are decreased and hardness is improved with the increasing of deformation. Different heat treatment experimental results show that when the cold rolling deformation within 0%-20%, after 980 ℃×10 min solution treatment, the recrystallization is incepted, grains are refined, deformed grains and dislocation are remained in the plate. When the deformation within 0%-20%, deformed grains are remained and recrystallized grain size is refined with the increasing of deformation, thus the hardness of solution treated plate is increased with the increasing of deformation. The recrystallization finished and work hardening is eliminated,thus the hardness of solution treated plate decline to undeformed level and remains unchanged when the deformation larger than 25%. The γ' and γ'' phases are precipitated in the plate after aging heat treatment, and the hardness of the plate is significantly higher than that of the cold rolled and solid solution treatment states, and the hardness is basically not affected by the deformation amount of cold rolling. The threshold value of cold rolling deformation for recrystallization inception of GH4169 alloy is within 5%-10% during 980 ℃ solution treatment. And the cold rolling deformation threshold value of complete recrystallization is about 25%. According to actual production condition, the optimal cold rolling deformation is larger than 25%, and the matched solution treatment is 980 ℃×10 min.