Twin nucleation from a single dislocation in hexagonal close-packed crystals
| Autor: | Lu Jiang, Andrew M. Minor, Velimir R. Radmilović, Julian E.C. Sabisch, Liang Qi, Mark Asta, Daryl C. Chrzan |
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| Rok vydání: | 2021 |
| Předmět: |
HRTEM
Materials science Polymers and Plastics Nucleation chemistry.chemical_element 02 engineering and technology 01 natural sciences Dissociation (chemistry) 0103 physical sciences HCP metals Density functional theory (DFT) High-resolution transmission electron microscopy 010302 applied physics Condensed matter physics Metals and Alloys Close-packing of equal spheres Rhenium 021001 nanoscience & nanotechnology Twin nucleation Electronic Optical and Magnetic Materials chemistry Transmission electron microscopy Ceramics and Composites Density functional theory 0210 nano-technology Crystal twinning Anisotropic elasticity |
| Zdroj: | Acta Materialia |
| ISSN: | 1359-6454 |
| DOI: | 10.1016/j.actamat.2020.10.038 |
| Popis: | Twinning plays an important role in governing the balance between strength and ductility in hexagonal-close-packed (HCP) metals. Here, we report a combined experimental and theoretical study of twin nucleation from a single dislocation in HCP crystals. Specifically, high-resolution transmission electron microscopy has been used to identify { 11 2 ¯ 1 } twin nuclei in HCP rhenium, providing evidence of their nucleation from a dislocation. The favorability of this dislocation-based nucleation mechanism is rationalized by an anisotropic elasticity model of dislocation dissociation, parametrized by density functional theory calculations, which suggests the conditions for disconnection nucleation and propagation, under which this { 11 2 ¯ 1 } twinning mechanism is expected to be effective. The analysis serves to advance our understanding of the origin of the unique predominance of { 11 2 ¯ 1 } twinning in rhenium, which correlates with the high strength and ductility featured by this metal. It also provides new insights into design strategies that may be effective in activating this twinning mode and enhancing the balance between strength and ductility in HCP alloys more broadly. |
| Databáze: | OpenAIRE |
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