冷轧变形量和热处理状态对GH4169合金板材组织及硬度的影响

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

对GH4169合金开展不同变形量的冷轧和热处理实验,分析不同冷轧变形量和随后的不同热处理状态对板材显微组织及硬度的影响。不同冷轧变形量研究结果表明:随着变形量的增加,冷轧板材中的位错密度升高并形成滑移带,织构组织逐渐增强,退火孪晶界逐渐消失,板材硬度随之增大。不同热处理状态研究分析表明:980℃×10 min固溶处理后,变形量小于20%时,板材中仍残留有变形晶粒和位错,随着变形量增加再结晶逐渐发生,晶粒度尺寸逐渐细化,板材硬度随变形量的增加而升高;变形量达到25%以上时,固溶态板材可完成再结晶,变形晶粒和冷作硬化基本消除,板材的硬度降低至未变形的水平并且不随变形量增加而改变;时效热处理后板材中析出γ''和γ'强化相,板材硬度显著高于冷轧态和固溶处理态且硬度基本不受冷轧变形量的影响;GH4169合金在980℃下固溶处理而发生再结晶的冷轧变形量门槛值处于5%~10%范围内,完全再结晶的冷轧变形量门槛值为25%左右。综合考虑实际生产情况,GH4169合金板材优化的制备工艺为冷轧变形量大于25%,相应的固溶处理制度宜选择为980℃×10 min。

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%.Theγ'andγ''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.