The University of Southampton
University of Southampton Institutional Repository
Warning ePrints Soton is experiencing an issue with some file downloads not being available. We are working hard to fix this. Please bear with us.

Phase evolution and mechanical properties of an intercritically-annealed Fe-10Ni-7Mn (wt. %) martensitic steel severely deformed by high-pressure torsion

Phase evolution and mechanical properties of an intercritically-annealed Fe-10Ni-7Mn (wt. %) martensitic steel severely deformed by high-pressure torsion
Phase evolution and mechanical properties of an intercritically-annealed Fe-10Ni-7Mn (wt. %) martensitic steel severely deformed by high-pressure torsion
Experiments were conducted on an Fe-10Ni-7Mn (wt. %) martensitic steel processed by high-pressure torsion (HPT) after intercritical annealing in the dual phase (α+γ) region at 600°C for 2 hours. Microstructural examination and phase analysis using electron backscatter diffraction (EBSD) confirmed that post-HPT processing led to a phase transformation of austenite to α-martensite (γ→α and γ→ε→α) such that after 20 turns of HPT the microstructure included multi-phases of α-martensite, austenite and ε-martensite. The HPT processing also produced a significant reduction in the α-martensite and austenite grain sizes from initial values of 3.8 and 3.9 μm to ~225 and ~60 nm after 20 HPT turns, respectively, while the ε-martensite final grain size was ~44 nm. Micro-hardness measurements and tensile testing showed a significant increase in hardness and in the ultimate tensile strength to about 680 Hv and 2235 MPa after 20 turns, respectively. Finally, the fracture surfaces of samples after HPT processing showed a combination of dimples, cracks and shear bands which confirmed a transition in fracture behavior from ductile to a mixture of a ductile and brittle mode.
high-pressure torsion, intercritical annealing, phase transformation, Microstructural evolution, mechanical properties
0921-5093
Kalahroudi, Faezeh J.
e95ed223-6ad2-473a-9811-4dd1484edf63
Koohdar, Hamidreza
6d616b2b-5bc8-4fe7-8f60-f57dcacedd72
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Nili-Ahmadabadi, Mahmoud
14b05165-fc44-4b5f-a21d-db078febeeeb
Kalahroudi, Faezeh J.
e95ed223-6ad2-473a-9811-4dd1484edf63
Koohdar, Hamidreza
6d616b2b-5bc8-4fe7-8f60-f57dcacedd72
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Nili-Ahmadabadi, Mahmoud
14b05165-fc44-4b5f-a21d-db078febeeeb

Kalahroudi, Faezeh J., Koohdar, Hamidreza, Langdon, Terence G and Nili-Ahmadabadi, Mahmoud (2020) Phase evolution and mechanical properties of an intercritically-annealed Fe-10Ni-7Mn (wt. %) martensitic steel severely deformed by high-pressure torsion. Materials Science and Engineering: A, [140519]. (doi:10.1016/j.msea.2020.140519).

Record type: Article

Abstract

Experiments were conducted on an Fe-10Ni-7Mn (wt. %) martensitic steel processed by high-pressure torsion (HPT) after intercritical annealing in the dual phase (α+γ) region at 600°C for 2 hours. Microstructural examination and phase analysis using electron backscatter diffraction (EBSD) confirmed that post-HPT processing led to a phase transformation of austenite to α-martensite (γ→α and γ→ε→α) such that after 20 turns of HPT the microstructure included multi-phases of α-martensite, austenite and ε-martensite. The HPT processing also produced a significant reduction in the α-martensite and austenite grain sizes from initial values of 3.8 and 3.9 μm to ~225 and ~60 nm after 20 HPT turns, respectively, while the ε-martensite final grain size was ~44 nm. Micro-hardness measurements and tensile testing showed a significant increase in hardness and in the ultimate tensile strength to about 680 Hv and 2235 MPa after 20 turns, respectively. Finally, the fracture surfaces of samples after HPT processing showed a combination of dimples, cracks and shear bands which confirmed a transition in fracture behavior from ductile to a mixture of a ductile and brittle mode.

Text
Kalahroudi-text-final - Accepted Manuscript
Download (3MB)

More information

Accepted/In Press date: 9 November 2020
e-pub ahead of print date: 12 November 2020
Keywords: high-pressure torsion, intercritical annealing, phase transformation, Microstructural evolution, mechanical properties

Identifiers

Local EPrints ID: 446208
URI: http://eprints.soton.ac.uk/id/eprint/446208
ISSN: 0921-5093
PURE UUID: aad89845-3bbb-4009-902b-242b8968a9ff
ORCID for Terence G Langdon: ORCID iD orcid.org/0000-0003-3541-9250

Catalogue record

Date deposited: 28 Jan 2021 17:32
Last modified: 26 Nov 2021 05:58

Export record

Altmetrics

Contributors

Author: Faezeh J. Kalahroudi
Author: Hamidreza Koohdar
Author: Mahmoud Nili-Ahmadabadi

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×