University of Oulu

Ali, M., Khosravifard, A., Hamada, A., Mattar, T., Eissa, M., & Kömi, J. (2023). Promotion of thermomechanical processing of 2-GPa low-alloyed ultrahigh-strength steel and physically based modelling of the deformation behaviour. In Materials Science and Engineering: A (Vol. 867, p. 144747). Elsevier BV.

Promotion of thermomechanical processing of 2-GPa low-alloyed ultrahigh-strength steel and physically based modelling of the deformation behaviour

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Author: Ali, Mohammed1,2; Khosravifard, Ali3; Hamada, Atef4;
Organizations: 1Materials and Mechanical Engineering, Centre for Advanced Steel Research, University of Oulu, P.O. Box 4200, FI-90014, Oulu, Finland
2Steel Technology Department, Central Metallurgical Research and Development Institute, Helwan, 11421, Egypt
3Department of Materials Engineering, Abadeh School of Higher Educations, Shiraz University, Abadeh, 73916, Iran
4Kerttu Saalasti Institute, Future Manufacturing Technologies (FMT), University of Oulu, Pajatie 5, Nivala, 85500, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 18.5 MB)
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Language: English
Published: Elsevier, 2023
Publish Date: 2023-09-08


A low-alloyed ultrahigh-strength steel comprising CrNiMoWMnV was designed based on thermodynamic calculations and by controlling the microalloying elements to promote various strengthening mechanisms upon processing. The hot deformation behaviour and mechanism were correlated with the processing parameters, that is, strain rate and temperature. The fine features of the deformed microstructures were analysed using electron backscatter diffraction (EBSD) and MATLAB software, combined with the MTEX texture and crystallographic analysis toolbox. The flow stress behaviour at high temperatures was modelled using the dislocation density-based Bergström's model, which could be applied up to the peak strain. However, the diffusional transformation (i.e. recrystallisation)-based Kolmogorov–Johnson–Mehl–Avrami model has been applied to fit the flow stress over a wide deformation strain. The effective grain size (EGS) of martensite and prior austenite grain size (PAGS) were correlated with the deformation temperature and strain rate. Because the PAGS was significantly refined from 16 μm in the initial microstructure to 6 μm after processing at 850 °C/0.01 s-1, the corresponding martensite EGSs were 1.38 and 1.01 μm, respectively. Therefore, these fine-controlled characteristics of the processed microstructures at high temperatures help to enhance the mechanical properties, such as the strength and toughness, of the designed ultrahigh-strength 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: 867
Article number: 144747
DOI: 10.1016/j.msea.2023.144747
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: The authors would like to thank the Finnish Foundation for Technology Promotion for their financial support during this work through the program of postdocs in company (PoDoCo). Atef Hamada would like to acknowledge the financial assistance of Business Finland, project FOSSA- Fossil-Free Steel Applications grant number 5498/31/2021.
Dataset Reference: The data that has been used is confidential.
Copyright information: © 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (