Segregation assisted microtwinning during creep of a polycrystalline L1(2)-hardened Co-base superalloy

Freund L, Messe OMDM, Barnard JS, Göken M, Neumeier S, Rae CMF (2017)


Publication Status: Published

Publication Type: Journal article

Publication year: 2017

Journal

Publisher: PERGAMON-ELSEVIER SCIENCE LTD

Book Volume: 123

Pages Range: 295-304

DOI: 10.1016/j.actamat.2016.10.048

Abstract

A polycrystalline L1(2)-hardened Co-base superalloy was creep deformed at 750 degrees 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, gamma and gamma'. 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 gamma' phase revealed segregation of elements known to decrease the stacking fault energy and a local depletion of gamma' 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. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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APA:

Freund, L., Messe, O.M.D.M., Barnard, J.S., Göken, M., Neumeier, S., & Rae, C.M.F. (2017). Segregation assisted microtwinning during creep of a polycrystalline L1(2)-hardened Co-base superalloy. Acta Materialia, 123, 295-304. https://dx.doi.org/10.1016/j.actamat.2016.10.048

MLA:

Freund, Lisa, et al. "Segregation assisted microtwinning during creep of a polycrystalline L1(2)-hardened Co-base superalloy." Acta Materialia 123 (2017): 295-304.

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