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

• Published in: iScience Vol. 25; no. 5; p. 104248
• Main Authors: Liu, Mao, Wang, Pengfei, Lu, Guoxing, Huang, Cheng-Yao, You, Zhong, Wang, Chien-He, Yen, Hung-Wei
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 20.05.2022; Elsevier
• Subjects: Materials mechanics; Mechanical property; Metals; Microstructure; Materials mechanics; Microstructure; Mechanical property; Metals
• ISSN: 2589-0042; 2589-0042
• DOI: 10.1016/j.isci.2022.104248

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. [Display omitted] •Deformation-activated recrystallization twin is enabled by cryogenic impact in pure Al•This new twinning path occurs during discontinuous dynamic recrystallization•Nucleation of these twinning grains prefers boundary edge and corner•Occurrence of new twinning mechanism depends on deformation orientation Materials mechanics; Mechanical property; Microstructure; Metals