Segregation assisted microtwinning during creep of a polycrystalline L12-hardened Co-base superalloy
| Autor: | O.M.D.M. Messé, Catherine M.F. Rae, Steffen Neumeier, Jonathan S. Barnard, Mathias Göken, Lisa P. Freund |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Polymers and Plastics Metallurgy Metals and Alloys 02 engineering and technology Slip (materials science) 021001 nanoscience & nanotechnology 01 natural sciences Electronic Optical and Magnetic Materials Superalloy Creep Deformation mechanism Stacking-fault energy 0103 physical sciences Ceramics and Composites Partial dislocations Crystallite Composite material 0210 nano-technology Crystal twinning |
| Zdroj: | Acta Materialia. 123:295-304 |
| ISSN: | 1359-6454 |
| DOI: | 10.1016/j.actamat.2016.10.048 |
| Popis: | A polycrystalline L12-hardened Co-base superalloy was creep deformed at 750 °C. The investigation of the deformed microstructure in the transmission electron microscope revealed microtwinning to be the prevailing deformation mechanism. The detected twins spanned the entire grain and cut through both, γ and γ′. Detailed high-resolution transmission electron microscopy investigations indicated that twin growth takes place by the slip of single a/6 〈112〉 partial dislocations along the twin boundary. Further analysis of the twin boundaries in the γ′ phase revealed segregation of elements known to decrease the stacking fault energy and a local depletion of γ′ forming elements. We propose that this segregation behavior enables subsequent a/6〈112〉 dislocations to easily slip along the twin boundary and further thicken the twins in the process. |
| Databáze: | OpenAIRE |
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