核电厂反应堆压力容器O型密封管用GH4169合金的热加工性能及组织演变

Hot processing performance and microstructure evolution of superalloy GH4169 for pressure vessel sealing pipes

利用Gleeble-3500热模拟试验机,研究了高温合金GH4169在温度1000~1150℃,应变速率0.01~10 s^(-1)变形参数下的热加工性能及组织演变规律。获得了合金的真应力-真应变曲线,随后构建了Arrhenius本构方程、加工图与热变形机理图。结果表明,增加应变速率或降低变形温度会导致变形抗力增大,其中1000℃下的变形抗力可达到400 MPa。合金在峰值应变与稳态应变下的热变形激活能分别为436.4696,399.20 kJ/mol;失稳加工窗口出现在3~10 s^(-1)的高应变速率区;而经1025~1075℃,0.05~0.6 s^(-1)变形后,出现晶粒尺寸为10μm的完全动态再结晶组织,因此该参数区间可作为GH4169合金的最佳热加工窗口。

The hot working properties and microstructure evolution of superalloy GH4169 were studied by Gleeble-3500 simulator under the deformation parameters of 1000~1150℃and 0.01~10 s^(-1).The true stress-true strain curves of the superalloy were obtained,and then the Arrhenius constitutive equation,processing map and deformation mechanism map were constructed.The results show that increasing the strain rate or decreasing the deformation temperature would lead to an increase in deformation resistance,which could reach 400 MPa at 1000℃.The activation energies of GH4169 at peak strain and stable strain were determined as 436.4696 kJ/mol and 399.20 kJ/mol,respectively.The instable processing window was at the higher strain rate region of 3~10 s^(-1).While fully dynamic recrystallization occurred with the grain size of 10μm deformed at 1025~1075℃and 0.05~0.6 s^(-1),therefore,this parameter interval could be used as the optimal processing window for GH4169.