University of Oulu

Barati Rizi, M. H., Ghiasabadi Farahani, M., Aghaahmadi, M., Kim, J. H., Karjalainen, L. P., & Sahu, P. (2022). Analysis of strain hardening behavior of a high-Mn TWIP steel using electron microscopy and cyclic stress relaxation. Acta Materialia, 240, 118309.

Analysis of strain hardening behavior of a high-Mn TWIP steel using electron microscopy and cyclic stress relaxation

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Author: Barati Rizi, Mohammad Hossein1; Ghiasabadi Farahani, Mehrdad2; Aghaahmadi, Mahdi3;
Organizations: 1School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran
2Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON K7L 3N6, Canada
3Department of Materials Science & Engineering, Hanbat National University, Yuseong-gu, Daejeon 34158, Republic of Korea
4Centre for Advanced Steels Research, University of Oulu, Oulu 90014, Finland
5Department of Physics, Jadavpur University, Kolkata 700032, India
Format: article
Version: accepted version
Access: embargoed
Persistent link:
Language: English
Published: Elsevier, 2022
Publish Date: 2024-09-05


Electron microscopy and cyclic stress relaxation experiments were employed to study the dislocation-obstacle interactions and activated hardening mechanisms, during tensile straining of a high-Mn TWIP steel specimen, and to estimate the contributions of hardening mechanisms to the strain hardening behavior. Electron contrast channeling and high-resolution electron backscattered diffraction images showed that deformation twins and their twin boundaries affect the dislocation evolutions inside both the matrix and twin lamellae. High-resolution transmission electron microscopy suggested that twin boundaries (TBs) can be passed by dislocations through the dislocation multiplication mechanism resulting in the nucleation of sessile dislocations and alternated stacking faults at TBs. Consequently, high dislocation density was developed behind the TBs resulting in enhancement of the strain hardening rate through the composite hardening effect. Various thermally activated parameters determined through cyclic stress relaxation tests indicated that dislocation evolution, developed by TBs in terms of the composite effect, was the prevalent rate-controlling mechanism, imparting higher strengthening than TBs in terms of the dynamic Hall–Petch effect. Finally, the high nucleation tendency of Shockley partial dislocations at TBs was interpreted from the variation of the stress exponent and independent plastic strain rate, and also from the general stacking fault energy point of view.

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Series: Acta materialia
ISSN: 1359-6454
ISSN-E: 1873-2453
ISSN-L: 1359-6454
Volume: 240
Article number: 118309
DOI: 10.1016/j.actamat.2022.118309
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: This work was supported by a grant from the National Research Foundation of Korea (NRF) funded by the Korean government (MSIT) (No. 2021R1A2B5B01002063).
Copyright information: © 2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http:/