University of Oulu

Tian Zhou, Yi Xiong, Xiaoqin Zha, Yun Yue, Yan Lu, Tian-tian He, Feng-zhang Ren, Ekta Rani, Harishchandra Singh, Jukka Kömi, Marko Huttula, Wei Cao, Hot-deformation-induced structural and mechanical properties of Ce-modified SAF 2507 super duplex stainless steel, Journal of Materials Research and Technology, Volume 9, Issue 4, 2020, Pages 8379-8390, ISSN 2238-7854,

Hot-deformation-induced structural and mechanical properties of Ce-modified SAF 2507 super duplex stainless steel

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Author: Zhou, Tian1; Xiong, Yi1,2; Zha, Xiaoqin3;
Organizations: 1School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, Henan, China
2Collaborative Innovation Center of Nonferrous Metals, Luoyang 471023, Henan, China
3Luoyang Ship Material Research Institute, Luoyang 471000, Henan, China
4National United Engineering Laboratory for Advanced Bearing Tribology, Henan University of Science and Technology, Luoyang 471023, Henan, China
5Nano and Molecular Systems Research Unit, University of Oulu, 90014 Oulu, Finland
6Materials and Mechanical Engineering, Center for Advanced Steels Research, University of Oulu, 90014 Oulu, Finland
7School of Mechanical and Automotive Engineering, Anhui Polytechnic University, Wuhu 241000, Anhui, China
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4.2 MB)
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Language: English
Published: Elsevier, 2020
Publish Date: 2020-12-01


A typical rare-earth element modified Ce-SAF 2507 super duplex stainless steel was isothermally hot-compressed to reach superior mechanic properties over its pristine and peers. Mechanical, macro- and micro-structural evolutions subjected to hot-modification were studied in detail toward an optimal hot working for the Ce-SAF2507. A dynamic softening phenomenon shows that the increase of hot deformation temperature and decrease of the strain rate were dominated by the dynamic recovery of ferrite at a high strain rate and low deformation temperature. The same phenomenon at a low strain rate but high deformation temperature was ruled by the dynamic recrystallization of austenite. These two processes determined significant phase transformations from austenite to ferrite under higher deformation temperature and strain rate. A hot deformation activation energy Q ∼406 kJ mol⁻¹ was obtained through a unified strain-compensated constitutive equation for Ce-SAF2507. Quantitative grain size refinements further proved the above mechanisms deduced from mechanical and microscopic observations, while structure induced changes of mechanical properties were crosschecked with the microhardness. Insights of microstructure also demonstrated the existences of the Cr₂N in both phases, grain boundaries, and α/γ interface. The overall deformation dynamics was explicated based on the structural and quantitative results.

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Series: Journal of materials research and technology
ISSN: 2238-7854
ISSN-E: 2214-0697
ISSN-L: 2238-7854
Volume: 9
Issue: 4
Pages: 8379 - 8390
DOI: 10.1016/j.jmrt.2020.05.123
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: This work was supported by the National Natural Science Foundation of China under grants Nos. U1804146 and 51801054, and by the Program for Science, Technology Innovation Talents in Universities of Henan Province (17HASTIT026), Education Department of Henan Province (16A430005) and the Science and Technology Innovation Team of Henan University of Science and Technology (2015XTD006). Financial supports from the Academy of Finland (311934) and Anhui Provincial Grant for high-level platform construction are also acknowledged.
Copyright information: © 2020 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (