TEM observation of nano-twinned precipitation phase Al₃Mg₂

Abstract

Friction stir welding (FSW) is a solid-phase bonding technique, which is suitable for bonding aluminium/magnesium dissimilar metals. In the present work, a nano-precipitated phase in 1060 Al/AZ31B Mg FSW joint was observed and analysed by transmission electron microscopy (TEM) and high-resolution electron microscopy (HRTEM). The type and morphology of the precipitated phase were determined. The results showed a nano-twinned precipitation phase, Al₃Mg₂, which was elliptical in shape and approximately 300 nm in size. In addition, the effective stacking fault energy (SFE) of nano-twinned Al₃Mg₂, approximately 3.51 mJ m⁻², was calculated using the first principles and the effective SFE equation. A low effective SFE was beneficial to the crystal twinning of Al₃Mg₂.

KEYWORDS:

• Nano-twinned precipitation phase
• Al₃Mg₂
• effective stacking fault energy
• TEM

Acknowledgements

We thank Dr Zheng from ZKKF (Beijing) Science and Technology Co., Ltd., for TEM observations.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was funded by the Postdoctoral Research Program of Henan Province [grant number 202003086], and Training Plan for Young Key Teachers in Colleges and Universities of Henan Province [grant number 2020GGJS236].