中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 26 No. 2 February 2016 |
（1. Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
3. Korea Institute of Materials Science, Changwon 641010, Korea）
Abstract:Dislocation mechanism operating in dynamic recrystallization (DRX) during hot compression of Mg-5.51Zn-0.49Zr alloy was investigated by X-ray diffraction, optical microscopy and transmission electron microscopy. The results showed that the continuous DRX occurred at a low strain rate of 1×10-3 s-1, which was associated with the operation of the single gliding dislocation climbing. At the intermediate strain rate of 1×10-2 s-1, the continuous DRX was associated with the climbing of the gliding dislocation array as deformed at an elevated temperature of 350 °C, and in contrast, the discontinuous DRX was observed and associated with the bulging of subgrain boundaries as the deformation temperature was raised to 400 °C. The continuous DRX was associated with the climbing of the leading dislocation ahead of pile-ups, and resultant rearrangement of misorientated flat dislocation pile-ups as the strain rate was increased to 1×100 s-1. It is suggested that the mechanism predominating the dislocation climbing was changed from the vacancy migration to the stress acting on the leading dislocation ahead of the pile-up as the strain rate was gradually increased.
Key words: magnesium alloy; dislocation; mechanism; dynamic recrystallization
