Active {112¯1} and {101¯2} extension twinning in a WE43 Mg alloy. (1st May 2023)

• Record Type: Journal Article
• Authors: Chen, W.Q.; Deng, S.; Zhao, X.J.; Luo, S.N.
• Is Part Of: Journal of materials science & technology. Volume 144(2023)
• Page Start: 93
• Page End: 101
• Publication Date: 2023-05-01
• Subjects: Mg alloy -- Plastic deformation -- Twinning -- Twin-twin interaction -- Twin-twin junction; Metals -- Periodicals; Materials science -- Periodicals; Materials science; Metals; Periodicals; 620.1105
• DOI: 10.1016/j.jmst.2022.09.055
• Languages: English
• ISSNs: 1005-0302

Abstract

Highlights: The interaction of co-zone {11 2 ¯ 1} twin variants can result in formation of crossing-like twin-twin junctions, different from those formed by interaction of co-zone {10 1 ¯ 2} twin variants. Four typical twin-twin junctions are observed for the interaction of the {11 2 ¯ 1} twins, including two types of crossing-like junctions. One type of the crossing-like junction is formed by nucleation of a new twin on the back side of the impeded twin, and the other type may be formed by the pre-existing twin simultaneously impeding two closely aligned incoming twins on its two sides. Twin nucleation is more likely to occur at {11 2 ¯ 1} twin boundary rather than at {10 1 ¯ 2} twin boundary, due to the relatively large strain concentration at the {11 2 ¯ 1} twin boundary. Abstract: Deformation twinning in a WE43 alloy subjected to uniaxial compression at room temperature is investigated. Active {11 2 ¯ 1} and {10 1 ¯ 2} extension twinning is observed. The activation of {11 2 ¯ 1} twinning in a certain grain is influenced not only by its own Schmid factor, but also by that of the basal slip. Twin-twin interactions of the co-zone {11 2 ¯ 1} twin variants are commonly observed and systematically studied, including the crystallographic characteristics of the four typically observed twin-twin junctions (TTJs) and the associated twin-twin boundaries. Unlike the quilted-looking TTJs formed by the interaction of co-zone {10 1 ¯ 2} twin variants, crossing-like TTJs of co-zone {11 2 ¯ 1} twin variants are observed and their formation mechanisms are discussed. Crossing-like TTJs are also formed by the interaction of {11 2 ¯ 1} and {10 1 ¯ 2} twins. The morphology and thickening rate of {11 2 ¯ 1} and {10 1 ¯ 2} twins vary markedly due to the difference in twinning shear. The needle-like {11 2 ¯ 1} twins thicken more slowly than the lenticular {10 1 ¯ 2} twins. Twin nucleation is observed on the previously formed {11 2 ¯ 1} twin boundary due to the relatively large strain concentration on such interface, while twin nucleation on {10 1 ¯ 2} twin boundary is rarely observed.