GH3028镍基合金的热变形动态再结晶及微观组织演变  

Dynamic Recrystallization and Microstructure Evolution of GH3028 Nickel Base Alloy

作　　者：徐翔民[1] 王占林 XU Xiang-min;WANG Zhan-lin(Yellow River Conservancy Technical Institute,Henan Kaifeng 475004,China;Kaifeng Technician College,Henan Kaifeng 475000,China)

机构地区：[1]黄河水利职业技术学院,河南开封475004 [2]开封技师学院,河南开封475000

出　　处：《精密成形工程》2022年第8期73-79,共7页Journal of Netshape Forming Engineering

基　　金：2020年开封市科技计划(2001020)。

摘　　要：目的研究GH3028镍基合金动态再结晶过程中的晶粒尺寸变化情况,明晰微观组织形貌的演变规律。方法利用DST3000PC型动态热模拟实验机,在温度为1050~1300℃、应变速率为1×10^(-3)~1×10^(-1) s^(-1)、最大应变量为58%的条件下对GH3028镍基合金进行热压缩实验,通过构建动态再结晶和晶粒尺寸演变数值计算模型并结合实验进行验证。结果峰值应力随温度的上升而有所下降,在1050~1300℃温度范围内,温度越高,合金试样越容易趋于稳态,动态再结晶特点越为明显。通过对实验数据进行优化和拟合,根据峰值应力值计算出热变形激活能Q为516 kJ/mol,进而求解出热变形方程。建立动态再结晶模型及晶粒尺寸模型,观察动态再结晶过程中的微观组织,发现当温度、应变速率不变时,动态再结晶的体积分数随应变量的增大而增大。温度的提升会显著增大动态再结晶体积分数和动态再结晶晶粒尺寸。晶粒尺寸受温度和应变速率的双重影响逐渐趋于稳态变化。结论通过对模型预测值与实际实验数据进行对比,发现该模型可以实现对晶粒尺寸变化的预测,模型预测平均晶粒尺寸与实验平均晶粒尺寸的相对误差为2.36%,说明该模型对动态再结晶晶粒尺寸的控制具有指导意义。The work aims to control the change of grain size during dynamic recrystallization of GH3028 nickel base alloy and clarify the evolution law of its microstructure.DST3000PC dynamic thermal simulation testing machine was adopted to conducted hot compression deformation of GH3028 nickel base alloy at 1050-1300℃,strain rate range of 1×10^(-3)^(-1)×10^(-1) s^(-1) and maximum strain of 58%.It was verified by dynamic recrystallization model and grain size evolution model in combination with experiment.The peak stress decreased with the increase of temperature.At 1050-1300℃,the higher the temperature,the more stable the alloy specimen,and the more obvious the dynamic recrystallization.Through the optimization and fitting of the experimental data,the activation energy of thermal deformation was calculated as 516 kJ/mol according to the peak stress value.The thermal deformation equation could be solved further.The dynamic recrystallization model and grain size model were established.It was found that the volume fraction of dynamic recrystallization increased with the increase of strain when the temperature and strain rate remained unchanged.The increase of temperature would significantly increase the volume fraction and grain size of dynamic recrystallization.The grain size tended to steady-state gradually under the effect of temperature and strain rate.Through comparison between the predicted data of the model and the actual experimental data,it is found that the model could predict the change of grain size.The relative error between the predicted average grain size of the model and the experimental average grain size is 2.36%,indicating that the model has guiding significance for the control of dynamic recrystallization grain size.

关 键 词：GH3028镍基合金 热变形 动态再结晶模型 晶粒尺寸演变 本构方程 微观组织变化 

分 类 号：TG156[金属学及工艺—热处理] TG146.15[金属学及工艺—金属学]