Dislocation-controlled formation and kinetics of grain boundary loops in two-dimensional crystals
| Autor: | Arran Curran, Roel P. A. Dullens, François A. Lavergne, Dirk G. A. L. Aarts |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Multidisciplinary
Materials science Misorientation Condensed matter physics 02 engineering and technology Deformation (meteorology) Plasticity 021001 nanoscience & nanotechnology Critical value 01 natural sciences Physical Sciences 0103 physical sciences Grain boundary Dislocation 010306 general physics 0210 nano-technology Optical vortex Burgers vector |
| Zdroj: | Proceedings of the National Academy of Sciences. 115:6922-6927 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.1804352115 |
| Popis: | The formation and kinetics of grain boundaries are closely related to the topological constraints imposed on their complex dislocation structure. Loop-shaped grain boundaries are unique structures to establish such a link because their overall topological "charge" is zero due to their null net Burgers vector. Here, we observe that a local rotational deformation of a 2D colloidal crystal with an optical vortex results in a grain boundary loop only if the product of its radius and misorientation exceeds a critical value. Above this value, the deformation is plastic and the grain boundary loop spontaneously shrinks at a rate that solely depends on this product, while otherwise, the deformation is elastically restored. We show that this elastic-to-plastic crossover is a direct consequence of the unique dislocation structure of grain boundary loops. At the critical value, the loop is structurally equivalent to the so-called "flower defect" and the shrinkage rate diverges. Our results thus reveal a general limit on the formation of grain boundary loops in 2D crystals and elucidate the central role of defects in both the onset of plasticity and the kinetics of grain boundaries. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|