Deformation-activated recrystallization twin: New twinning path in pure aluminum enabled by cryogenic and rapid compression

Mao Liu; Pengfei Wang; Guoxing Lu; Cheng-Yao Huang; Zhong You; Chien-He Wang; Hung-Wei Yen

doi:10.1016/j.isci.2022.104248

Deformation-activated recrystallization twin: New twinning path in pure aluminum enabled by cryogenic and rapid compression

iScience. 2022 Apr 14;25(5):104248. doi: 10.1016/j.isci.2022.104248. eCollection 2022 May 20.

Authors

Mao Liu^{1

2}, Pengfei Wang³, Guoxing Lu², Cheng-Yao Huang^{4

5}, Zhong You⁶, Chien-He Wang^{4

5}, Hung-Wei Yen^{4

5}

Affiliations

¹ School of Metallurgy, Northeastern University, Shenyang, 110819, China.
² Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC 3122, Australia.
³ CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China.
⁴ Department of Materials Science and Engineering, National Taiwan University, Roosevelt Road, Taipei 10617, Taiwan.
⁵ Advanced Research Center for Green Materials Science and Technology, National Taiwan University, Taipei 10617, Taiwan.
⁶ Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK.

Abstract

Bulk aluminum rarely forms deformation or annealing twins owing to its high stacking fault energy. We report a novel twinning mechanism mediated by dynamic recrystallization in 6N pure aluminum under high strain rate (∼1.3 × 10⁴ s^-1) impact at a cryogenic temperature (77 K). Discontinuous dynamic recrystallization occurs during rapid severe plastic deformation and generates inhomogeneous microstructures exhibiting low-angle and high-angle grain boundaries. Unexpectedly, Σ3 twin boundaries were able to develop during dynamic recrystallization. Although these recrystallization twins have similar morphology as that of annealing twins, their formation relies on deformation activation instead of thermal activation, which was suppressed by the cryogenic experiment. Besides, strong orientation dependence was observed for formation of these novel twins. Beyond annealing and deformation twin, deformation-activated recrystallization twin is a new path for pure aluminum twinning.

Keywords: Materials mechanics; Mechanical property; Metals; Microstructure.