中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 35 No. 7 July 2025 |
（1. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China;
2. State Key Laboratory of Precision Manufacturing for Extreme Service Performance, Central South University, Changsha 410083, China;
3. Rongcheng Huadong Metal-forming Machinery Co. Ltd., Rongcheng 264300, China;
4. Guizhou Anda Aviation Forging Co. Ltd., Anshun 561005, China;
5. South Ural State University, 76 Lenin Av., Chelyabinsk 454080, Russia）
Abstract:The effects of varying strain rates and deformation temperatures on the microstructure evolution of the FGH4113A alloy were investigated through hot compression experiments. During hot deformation, grain evolution is primarily governed by dynamic recrystallization (DRX) and twinning primarily. Furthermore, the pinning effect of the primary γ'''' phase (γ''''p phase) plays a crucial role in grain refinement. Lower strain rates or higher temperatures facilitate DRX, twinning, and the dissolution of the γ''''p phase. At 1140 °C, significant dissolution of the γ''''p phase and the subsequent loss of its pinning effect reduce twinning activity. A unique twinning mechanism, termed “pinning twinning”, is identified, occurring exclusively under the influence of the pinning effect. When grain boundary migration fails to accommodate dislocations due to the pinning effect, grains preferentially eliminate dislocations via twinning, thereby reducing local strain energy. The grain size prediction model is improved by considering the pinning effect.
Key words: nickel-based superalloy; hot deformation; dynamic recrystallization; twinning; γ'' phase; pinning effect
