Twinning dislocations on {1¯011} and {1¯013} planes in hexagonal close-packed crystals
| Autor: | J. P. Hirth, Irene J. Beyerlein, Carlos N. Tomé, Jun Wang |
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| Rok vydání: | 2011 |
| Předmět: |
Materials science
Polymers and Plastics Condensed matter physics Molecular statics Metals and Alloys Close-packing of equal spheres Crystal structure Crystallographic defect Electronic Optical and Magnetic Materials Crystal Crystallography Ceramics and Composites Dislocation Deformation (engineering) Crystal twinning |
| Zdroj: | Acta Materialia. 59:3990-4001 |
| ISSN: | 1359-6454 |
| DOI: | 10.1016/j.actamat.2011.03.024 |
| Popis: | The objective of this investigation was to identify the elementary twinning dislocations (TDs) for { 1 ¯ 0 1 1 } and { 1 ¯ 0 1 3 } twins by fully characterizing their structure for an Mg crystal. For both { 1 ¯ 0 1 1 } and { 1 ¯ 0 1 3 } twins, we conclude that the 2-layer TD, not the 4-layer TD, is the active TD in twinning. The 4-layer TD can be considered as the combination of two 2-layer TDs with opposite-sign screw components. Molecular statics simulations of the Peierls energy show why the TDs of both twinning modes (for c/a ratios > 1.5) are only activated when the c-axis experiences a compressive strain. The simulations predict that 2-layer TDs are more mobile than 4-layer TDs and that the mobility of these twinning dislocations depends strongly on dislocation character. Correspondingly, the influence of TDs involved in deformation twinning processes on deformation twins is discussed. |
| Databáze: | OpenAIRE |
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