Symmetric or asymmetric glide resistance to twinning disconnection?

• Published in: npj computational materials Vol. 8; no. 1; pp. 1 - 7
• Main Authors: Gong, Mingyu, Ma, Houyu, Yang, Kunming, Liu, Yue, Nie, Jian-Feng, Wang, Jian
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 16.08.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/1023/1026; 639/301/1034/1035; Achievement tests; Asymmetry; Characterization and Evaluation of Materials; Chemistry and Materials Science; Computational Intelligence; Crystallography; Deformation; Gliding; Magnesium base alloys; Materials Science; Mathematical and Computational Engineering; Mathematical and Computational Physics; Mathematical Modeling and Industrial Mathematics; Microscopy; Propagation; Shear deformation; Symmetry; Theoretical; Twinning
• ISSN: 2057-3960; 2057-3960
• DOI: 10.1038/s41524-022-00855-y

Successive gliding of twinning disconnections (TDs) creates three-dimensional twins in parent crystal and accommodates shear deformation. It is generally recognized that TD is subject to the same Peierls stress as it glides forward or backward because of its dislocation character and the twofold rotation symmetry of the twin plane. Based on atomistic simulations, we demonstrate that the glide of TDs may be subject to a symmetric or asymmetric resistance corresponding to step character, symmetric resistance for A/A type steps but asymmetric resistance for A/B type steps, where A and B represent crystallographic planes in twin and matrix. Furthermore, we experimentally demonstrate that the asymmetric resistance results in asymmetric propagation and growth of twins in Mg alloys.