锻态GH4169合金热变形本构方程及热加工图

Constitutive Equation for Hot Deformation and Hot Processing Map of Wrought GH4169 Superalloy

目的研究锻态GH4169合金的热变形行为,获得优化的热加工参数。方法采用Gleeble 3500热模拟实验机对锻态GH4169合金进行不同工艺参数的热压缩实验,建立锻态GH4169合金的热变形本构方程,分析流变应力与热加工参数之间的关系。根据获得的流变应力–应变曲线建立锻态GH4169合金的热加工图。采用金相显微镜观察锻态GH4169合金变形后的显微组织。结果锻态GH4169合金的应力随变形温度的增加和应变速率的降低而降低。基于锻态GH4169合金的热加工图可知,锻态GH4169合金可热加工的区域分别为987~1027℃/0.026~0.01 s^(-1)和1070~1100℃/0.026~0.01 s^(-1),最优热加工参数分别为1000℃/0.01 s^(-1)和1100℃/0.01 s^(-1)。通过金相组织结果分析可知,锻态GH4169合金无论在低温高应变速率条件下,还是在高温低应变速率条件下都发生了再结晶。对于热加工图中的流变失稳区,合金的动态再结晶主要与变形热有关。对于热加工图中可热加工的区域,合金的变形机制主要是动态再结晶。结论通过对锻态GH4169合金热变形本构方程和热加工图进行研究,获得了锻态GH4169合金优化的热加工参数,可用于指导锻态GH4169合金的镦粗和环轧成形加工。

The work aims to investigate the hot deformation behavior of wrought GH4169 superalloy and obtain the optimal hot processing parameters.Gleeble 3500 thermal simulator was used to carry out hot compression experiments on wrought GH4169 superalloy with different processing parameters.Then,the constitutive equation for hot deformation of wrought GH4169 superalloy was established and the relationship between flow stress and hot processing parameters was analyzed.Next,the hot processing map of wrought GH4169 superalloy was established based on the flow stress-strain curve.Finally,the deformed microstructure was observed by metallographic microscope.The flow stress of the wrought GH4169 superalloy decreased with the increase of deformation temperature and the reduction of strain rate.Based on the hot processing map,the best hot processing regions of wrought GH4169 superalloy were 987-1027℃/0.026-0.01 s‒1 and 1070-1100℃/0.026-0.01 s^(-1),respectively and the optimal hot processing parameters were 1000℃/0.01 s^(-1)and 1100℃/0.01 s^(-1),respectively.Based on the microstructure analysis,the wrought GH4169 superalloy underwent dynamic recrystallization either at low temperature and high strain rate or at high temperature and low strain rate.In the flow stress instability region in the hot processing map,the dynamic recrystallization of the superalloy was mainly related to the deformation heat.In the available hot process region in the map,the deformation mechanism was mainly the dynamic recrystallization of the superalloy.Through the study on constitutive equation of hot deformation and the hot processing map of the wrought GH4169 superalloy,the optimal hot processing parameters have been obtained,which can be used to guide the upsetting and ring rolling of the wrought GH4169 superalloy.