University of Oulu

Ghafouri, M., Afkhami, S., Pokka, A.-P., Javaheri, V., Togiani, A., Larkiola, J., & Björk, T. (2024). Effect of temperature on the plastic flow and strain hardening of direct-quenched ultra-high strength steel S960MC. Thin-Walled Structures, 194, 111319.

Effect of temperature on the plastic flow and strain hardening of direct-quenched ultra-high strength steel S960MC

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Author: Ghafouri, Mehran1; Afkhami, Shahriar1; Pokka, Aki-Petteri2;
Organizations: 1Laboratory of Steel Structures, LUT University, Lappeenranta 53850, Finland
2Materials and Mechanical Engineering, University of Oulu, P.O. Box 4200, Oulu 90014, Finland
3Laboratory of Production Engineering, LUT University, Lappeenranta 53850, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 11.1 MB)
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Language: English
Published: Elsevier, 2023
Publish Date: 2023-11-08


This study investigates the plastic deformation and hardening behavior of the direct-quenched ultra-high strength steel S960MC at various temperatures ranging from room temperature to 900 ℃. In this regard, the Hollomon and Voce equations are used to model the hardening behavior of the material at different temperatures. The suitability of each equation to predict the plastic flow of S960MC is evaluated based on the best resulted fit for the material. In addition, microstructural investigations are carried out to indicate the correlations between the microstructural changes, occurring in the range of room temperature to 900 ℃, and hardening behavior and governing parameters. The Hollomon approach showed deviations from the experimental results for room to intermediate temperatures; however, the Voce equation modeled the material’s strain hardening and flow behavior more successfully for the entire temperature range of room temperature–900 ℃. Additionally, there was a significant consistency between the Kocks-Mecking and Voce parameters. Dislocation interactions, dynamic strain aging, dynamic recrystallization, dynamic recovery, tempering (martensite decomposition), and austenite formation were the most influential microstructural features on the hardening behavior at various temperatures. The correlations between these microstructural features and hardening parameters were established satisfactorily for both the Hollomon and Voce approaches.

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Series: Thin-walled structures
ISSN: 0263-8231
ISSN-E: 1879-3223
ISSN-L: 0263-8231
Volume: 194
Article number: 111319
DOI: 10.1016/j.tws.2023.111319
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
214 Mechanical engineering
212 Civil and construction engineering
Funding: This study was primarily a scientific collaboration between LUT University and the University of Oulu, financially supported as a part of the FOSSA project, funded by Business Finland. All industrial and academic partners of this project are highly appreciated. The authors also appreciate the support of SSAB Europe in providing the engaged research teams with the required raw material. Vahid Javaheri would also like to thank Jane ja Aatos Erkon säätiö (JAES) and Tiina ja Antti Herlinin säätiö (TAHS) for their financial support on the Advanced Steels for Green Planet project.
Copyright information: © 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (