Investigation on the microstructure evolution and dynamic recrystallization mechanisms of TiAl alloy at elevated temperature

Journal of Materials Research and Technology

Yonggang Yang¹  Anrui He²  Siyuan Zhang²  Haitao Jiang²  Shiwei Tian²  Yefei Zhang²  Yun Zhang²  Jianhua Liu² 

[1] Department of Materials Science and Engineering, KTH Royal Institute of Technology, Brinellvägen 23, Stockholm, SE-10044, Sweden;Institute of Engineering and Technology, University of Science and Technology Beijing, Beijing, 100083, China;

关键词: TiAl alloy;    Microstructure evolution;    Deformation;    Hot processing map;    Dynamic recrystallization;   

DOI  :  

来源: DOAJ

【 摘 要 】

The flow stress–strain curves appear to be sensitive to deformation conditions. The ratio of critical strain to peak strain εc/εp follows a linear relationship except when the temperature is 1240 °C and the strain rate is 0.001 s−1. During the deformation, the fragmentation and decomposition of γ/α2 lamellae are related to recrystallization of α2 and γ laths in the lamellae and the γ → α2 phase transformation, the former depends on dislocation slip and twinning, and the latter is related to temperature, local stress concentration and diffusion time. As for the recrystallization mechanisms, the γ phase is discontinuous dynamic recrystallization (DDRX) mode, while the α2 phase relies on continuous dynamic recrystallization (CDRX) mode. The β phase has more low-angle grain boundaries (LAGB) during deformation, indicating the continuous coordinated deformation, and this explains the enlarged hot working window of the TiAl alloy (1165–1240 °C/0.001 ~ 1 s−1 and 1120–1165 °C/0.001–0.4 s−1).

【 授权许可】

Unknown