中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 35 No. 5 May 2025 |
（1. School of Mechanical Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, China;
2. North China Electric Power Research Institute Co., Ltd., Beijing 100045, China;
3. Welding Institute, Central Iron & Steel Research Institute, Beijing 100081, China;
4. Hydrogen Energy Research Centre, Beijing Institute of Petrochemical Technology, Beijing 102617, China;
5. State Key Laboratory of Tribology in Advanced Equipment, Tsinghua University, Beijing 100084, China）
Abstract:The effects of rejuvenation heat treatment (RHT) on the serrated flow behavior and fracture mode of nickel- based superalloys (R26) were investigated by tensile tests and microstructural characterization. The serrated flow activation energies were determined to be 41-72 and 64-81 kJ/mol before and after RHT, respectively. Dynamic strain aging in the alloy is caused by the diffusion of carbon atoms into dislocation channels in the nickel matrix. Before RHT, carbides are concentrated at the grain boundaries. Cracks initiate from these carbides and propagate along the grain boundaries. RHT dissolves carbides at grain boundaries, transferring crack initiation to the precipitated phase group in the grains. RHT increases carbon atom concentration in the nickel matrix, enhancing dynamic strain aging and serrated flow behavior.
Key words: rejuvenation heat treatment; nickel-based superalloy; serrated flow behavior; fracture; activation energy
