Effect of post-deformation annealing on the microstructure and mechanical behavior of an Fe-Ni-Mn steel processed by high-pressure torsion
Effect of post-deformation annealing on the microstructure and mechanical behavior of an Fe-Ni-Mn steel processed by high-pressure torsion
Research was conducted to investigate the effects of high-pressure torsion (HPT) and post-deformation annealing (PDA) on the microstructure evolution and mechanical behavior of an Fe-9.6Ni-7.1Mn (at.%) steel with an initial lath martensitic microstructure. The experimental results showed that HPT processing led to the formation of an ultrafine grain martensitic microstructure accompanied by small amounts of strain-induced austenite. Phase analysis and microstructural examination confirmed that during PDA at 600 °C a large fraction of fine and coaxial austenite grains was introduced in the microstructure by diffusionless shear mechanism whereas its volume fraction at ambient temperature was drastically decreased by increasing the annealing time. Also, the grain size was reduced from a value of about 5.2 µm in the solution-treated specimen to ultrafine values of about 570 and 280 nm for the martensite and austenitic phases, respectively, after PDA for 7.2 ks. PDA yielded an outstandingly good combination of an ultimate tensile strength (1340 MPa) and fracture strain (11.9%) in comparison to the solution-annealed condition which can be attributed to the finer grain size and the presence of shear-formed austenite in the microstructure. In addition, the fracture mode changed from a fully ductile nature in the solution-treated specimen to a combination of ductile and brittle nature after applying the HPT and then returned again to a ductile behavior after PDA.
Fe-Ni-Mn steel, High-pressure torsion, Mechanical behavior, Microstructural evolution, Post-deformation annealing
1537-1546
Koohdar, Hamidreza
6d616b2b-5bc8-4fe7-8f60-f57dcacedd72
Nili-Ahmadabadi, Mahmoud
14b05165-fc44-4b5f-a21d-db078febeeeb
Kalahroudi, Faezeh Javadzadeh
6ac94931-e197-408d-ab0e-ec1560f6882e
Jafarian, Hamid Reza
bf2e9f85-c8db-424e-bfa2-7ae8f1717958
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
1 November 2021
Koohdar, Hamidreza
6d616b2b-5bc8-4fe7-8f60-f57dcacedd72
Nili-Ahmadabadi, Mahmoud
14b05165-fc44-4b5f-a21d-db078febeeeb
Kalahroudi, Faezeh Javadzadeh
6ac94931-e197-408d-ab0e-ec1560f6882e
Jafarian, Hamid Reza
bf2e9f85-c8db-424e-bfa2-7ae8f1717958
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Koohdar, Hamidreza, Nili-Ahmadabadi, Mahmoud, Kalahroudi, Faezeh Javadzadeh, Jafarian, Hamid Reza and Langdon, Terence G
(2021)
Effect of post-deformation annealing on the microstructure and mechanical behavior of an Fe-Ni-Mn steel processed by high-pressure torsion.
Journal of Materials Research and Technology, 15, .
(doi:10.1016/j.jmrt.2021.08.135).
Abstract
Research was conducted to investigate the effects of high-pressure torsion (HPT) and post-deformation annealing (PDA) on the microstructure evolution and mechanical behavior of an Fe-9.6Ni-7.1Mn (at.%) steel with an initial lath martensitic microstructure. The experimental results showed that HPT processing led to the formation of an ultrafine grain martensitic microstructure accompanied by small amounts of strain-induced austenite. Phase analysis and microstructural examination confirmed that during PDA at 600 °C a large fraction of fine and coaxial austenite grains was introduced in the microstructure by diffusionless shear mechanism whereas its volume fraction at ambient temperature was drastically decreased by increasing the annealing time. Also, the grain size was reduced from a value of about 5.2 µm in the solution-treated specimen to ultrafine values of about 570 and 280 nm for the martensite and austenitic phases, respectively, after PDA for 7.2 ks. PDA yielded an outstandingly good combination of an ultimate tensile strength (1340 MPa) and fracture strain (11.9%) in comparison to the solution-annealed condition which can be attributed to the finer grain size and the presence of shear-formed austenite in the microstructure. In addition, the fracture mode changed from a fully ductile nature in the solution-treated specimen to a combination of ductile and brittle nature after applying the HPT and then returned again to a ductile behavior after PDA.
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Koohdar-Revised Manuscript-TGL
- Accepted Manuscript
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1-s2.0-S2238785421009601-main (1)
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More information
Accepted/In Press date: 29 August 2021
e-pub ahead of print date: 8 September 2021
Published date: 1 November 2021
Additional Information:
Funding Information:
One of the authors was supported by the European Research Council under ERC Grant Agreement No. 267464-SPDMETALS (TGL) .
Publisher Copyright:
© 2021 The Author(s)
Keywords:
Fe-Ni-Mn steel, High-pressure torsion, Mechanical behavior, Microstructural evolution, Post-deformation annealing
Identifiers
Local EPrints ID: 451553
URI: http://eprints.soton.ac.uk/id/eprint/451553
ISSN: 2238-7854
PURE UUID: 17afa3d1-2661-4c19-b065-a205520aabb0
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Date deposited: 07 Oct 2021 16:31
Last modified: 17 Mar 2024 02:55
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Contributors
Author:
Hamidreza Koohdar
Author:
Mahmoud Nili-Ahmadabadi
Author:
Faezeh Javadzadeh Kalahroudi
Author:
Hamid Reza Jafarian
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