中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 35 No. 11 November 2025 |
（1. State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China;
2. Daye Special Steel Co., Ltd., Huangshi 435001, China;
3. Hubei Huangshi Kechuang Mold Technology Research Institute Co., Ltd., Huangshi 435007, China）
Abstract:The high-temperature deformation and dynamic recrystallization (DRX) behaviors of GH4698 superalloy were investigated via hot compression tests, and an improved unified dislocation density-based constitutive model was established. The results indicate that with the temperature decreasing or the strain rate increasing, the flow stress increases and the DRX fraction decreases. However, as the strain rate increases from 1 to 10 s-1, rapid dislocation multiplication and deformation heat accelerate the DRX nucleation, which further increases the DRX fraction. Discontinuous DRX nucleation is the dominant DRX nucleation mechanism, and continuous DRX nucleation mainly occurs under low strain rates. For the developed improved unified dislocation density-based constitutive model, the correlation coefficient, average absolute relative error, and root mean square error between the measured and predicted stresses are 0.994, 7.32% and 10.8 MPa, respectively. Meanwhile, the correlation coefficient between the measured and predicted DRX fractions is 0.976. These indicate that the developed model exhibits high accuracy in predicting the high-temperature deformation and DRX behaviors of GH4698 superalloy.
Key words: Ni-based superalloy; constitutive model; high-temperature deformation; dynamic recrystallization
