Dynamic spheroidisation behaviour of the lamellar Ti–22Al–25Nb alloy during hot compression

ABSTRACT

The dynamic spheroidisation behaviour of the lamellar Ti–22Al–25Nb alloy during hot compression at 970°C/0.01 s⁻¹ and strain of 30%, 50% and 70% was investigated. The results showed the lamellar-O phase that participated in the B2 matrix could be obtained by hot pressed sintering from pre-alloy powders. The corresponding scanning electron microscopy, electron backscattered diffraction and transmission electron microscopy observations indicated that the dynamic spheroidisation process can be divided into three stages, the first is the primary interphase high-energy defect stage, introduced by dislocation migration twinning and localised shearing. The second is the separation, and the last is the spheroidisation stages, which could be explained by boundary splitting and termination migration.

KEYWORDS:

• Ti₂AlNb
• lamellar microstructure
• hot compression
• dynamic spheroidisation

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This work was supported by the Program for Changjiang Scholars and Innovative Research Team in University (IRT1229), the National Natural Science Foundation of China (51275129) and the National Science and Technology Major Project of China (2014ZX04001-141).