University of Oulu

Khatami-Hamedani, H., Zarei-Hanzaki, A., Abedi, H. R., Anoushe, A. S., & Karjalainen, L. P. (2020). Dynamic restoration of the ferrite and austenite phases during hot compressive deformation of a lean duplex stainless steel. Materials Science and Engineering: A, 788, 139400.

Dynamic restoration of the ferrite and austenite phases during hot compressive deformation of a lean duplex stainless steel

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Author: Khatami-Hamedani, H.1; Zarei-Hanzaki, A.1; Abedi, H.R.1;
Organizations: 1Hot Deformation & Thermomechanical Processing of High Performance Engineering Materials Lab., School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, Tehran, Iran
2Centre for Advanced Steels Research, University of Oulu, Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 5.8 MB)
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Language: English
Published: Elsevier, 2020
Publish Date: 2022-05-05


The active restoration processes within the ferrite and austenite phases were investigated in a Ni-free duplex stainless steel with the 75/25 austenite/ferrite ratio performing compression tests over the wide range of temperature and strain rate (700–1000 °C and 0.001–0.1s−1, respectively). The substructural features under different Zener-Hollomon parameters (Z) were examined using the electron backscatter diffraction analysis. A significant portion of flow softening was attributed to the active softening mechanisms in the continuous network of ferrite phase. The ferrite was softened through continuous dynamic recrystallization (CDRX) at high Z values, but the dynamic recovery (DRV) surmounted CDRX at low Z parameters. Interestingly, the discontinuous dynamic recrystallization (DDRX) mechanism was testified by increasing temperature and strain rate, i.e. at medium Z values. DDRX occurred by the growth of high-angle subgrains near the austenite/ferrite interfaces. With decreasing Z values, an increase in subgrain and grain sizes was observed. Contrarily to ferrite, the austenite phase was softened mostly through the dynamic recovery mechanism. At higher Z values microband arrays were formed in austenite holding specific character resembling to band-like misorientation gradients. However, under the lower Z values, a small fraction of recrystallized grains was formed through the CDRX/DDRX mechanisms. This was justified considering the lower strain accommodation in the austenite phase during deformation of duplex stainless steel.

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Series: Materials science & engineering. A, Structural materials: properties, microstructure and processing
ISSN: 0921-5093
ISSN-E: 1873-4936
ISSN-L: 0921-5093
Volume: 788
Article number: 139400
DOI: 10.1016/j.msea.2020.139400
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Copyright information: © 2020 Published by Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 license