The effect of high-pressure torsion on the microstructure and outstanding pseudoelasticity of a ternary Fe-Ni-Mn shape memory alloy
The effect of high-pressure torsion on the microstructure and outstanding pseudoelasticity of a ternary Fe-Ni-Mn shape memory alloy
Experiments were conducted to examine the effect of high-pressure torsion (HPT) processing on the microstructure and pseudoelastic behavior of a ternary Fe–10Ni–7Mn (wt.%) shape memory alloy in both the solution-annealed and intercritically-annealed conditions. X-ray diffraction (XRD) patterns and electron backscatter diffraction (EBSD) analyses showed that the initial microstructure of the alloy in the solution-annealed condition was a fully lath α′-martensite which partially transformed to a strain-induced austenite (α′→γ) by HPT processing. Also, the austenite formed in the dual phase (α′+γ) specimens after intercritical annealing treatment at 600 °C for 7.2 ks underwent a γ→ε→α′ transformation during subsequent HPT processing such that a multi-phase microstructure was formed consisting of α′-martensite, austenite and ε-martensite. The HPT processing led to a significant increase in the microhardness value to ~690 Hv due to a high density of dislocations and the associated grain refinement of the microstructure. Cyclic loading-unloading tensile tests at room temperature revealed a strain hysteresis and pseudoelastic behavior in the HPT-processed specimens with different initial microstructures. Outstanding pseudoelasticity values of about 67% and 75% were obtained at the fourteenth loading-unloading cycle after 20 HPT turns in the solution-annealed and intercritically-annealed specimens, respectively.
High-pressure torsion, Microstructural evolution, Pseudoelastic behavior, Strain hysteresis, Ternary Fe-Ni-Mn shape memory alloy
Koohdar, Hamidreza
6d616b2b-5bc8-4fe7-8f60-f57dcacedd72
Nili-Ahmadabadi, Mahmoud
14b05165-fc44-4b5f-a21d-db078febeeeb
Kalahroudi, Faezeh J.
e95ed223-6ad2-473a-9811-4dd1484edf63
Jafarian, Hamidreza
2d3dd302-34fa-4066-9ed2-31daecc0c170
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
20 January 2021
Koohdar, Hamidreza
6d616b2b-5bc8-4fe7-8f60-f57dcacedd72
Nili-Ahmadabadi, Mahmoud
14b05165-fc44-4b5f-a21d-db078febeeeb
Kalahroudi, Faezeh J.
e95ed223-6ad2-473a-9811-4dd1484edf63
Jafarian, Hamidreza
2d3dd302-34fa-4066-9ed2-31daecc0c170
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Koohdar, Hamidreza, Nili-Ahmadabadi, Mahmoud, Kalahroudi, Faezeh J., Jafarian, Hamidreza and Langdon, Terence G
(2021)
The effect of high-pressure torsion on the microstructure and outstanding pseudoelasticity of a ternary Fe-Ni-Mn shape memory alloy.
Materials Science and Engineering: A, 802, [140647].
(doi:10.1016/j.msea.2020.140647).
Abstract
Experiments were conducted to examine the effect of high-pressure torsion (HPT) processing on the microstructure and pseudoelastic behavior of a ternary Fe–10Ni–7Mn (wt.%) shape memory alloy in both the solution-annealed and intercritically-annealed conditions. X-ray diffraction (XRD) patterns and electron backscatter diffraction (EBSD) analyses showed that the initial microstructure of the alloy in the solution-annealed condition was a fully lath α′-martensite which partially transformed to a strain-induced austenite (α′→γ) by HPT processing. Also, the austenite formed in the dual phase (α′+γ) specimens after intercritical annealing treatment at 600 °C for 7.2 ks underwent a γ→ε→α′ transformation during subsequent HPT processing such that a multi-phase microstructure was formed consisting of α′-martensite, austenite and ε-martensite. The HPT processing led to a significant increase in the microhardness value to ~690 Hv due to a high density of dislocations and the associated grain refinement of the microstructure. Cyclic loading-unloading tensile tests at room temperature revealed a strain hysteresis and pseudoelastic behavior in the HPT-processed specimens with different initial microstructures. Outstanding pseudoelasticity values of about 67% and 75% were obtained at the fourteenth loading-unloading cycle after 20 HPT turns in the solution-annealed and intercritically-annealed specimens, respectively.
Text
Koohdar-manuscript-TGL
- Accepted Manuscript
More information
Accepted/In Press date: 5 December 2020
e-pub ahead of print date: 10 December 2020
Published date: 20 January 2021
Additional Information:
Funding Information:
One of the authors (HK) expresses his thanks to Iran National Science Foundation (INSF) for partial financial support of this research. Another author was supported by the European Research Council under ERC Grant Agreement No. 267464-SPDMETALS (TGL).
Publisher Copyright:
© 2020 Elsevier B.V.
Keywords:
High-pressure torsion, Microstructural evolution, Pseudoelastic behavior, Strain hysteresis, Ternary Fe-Ni-Mn shape memory alloy
Identifiers
Local EPrints ID: 446211
URI: http://eprints.soton.ac.uk/id/eprint/446211
ISSN: 0921-5093
PURE UUID: b7b74160-349a-465d-80f6-ecbecfa34bbf
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Date deposited: 28 Jan 2021 17:32
Last modified: 17 Mar 2024 06:12
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Contributors
Author:
Hamidreza Koohdar
Author:
Mahmoud Nili-Ahmadabadi
Author:
Faezeh J. Kalahroudi
Author:
Hamidreza Jafarian
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