Microstructure and mechanical properties of an Fe–Mn–Al–C lightweight steel after dynamic plastic deformation processing and subsequent aging
Microstructure and mechanical properties of an Fe–Mn–Al–C lightweight steel after dynamic plastic deformation processing and subsequent aging
An austenitic low-density steel was processed by dynamic plastic deformation (DPD) over the strain range from 0.25 to 0.75 followed by aging at 450°C and then it was subjected to compressive testing at strain rates of 1.0 × 10-3 − 2.0 × 103 s-1. The results show that fine grain structures with high density dislocations are achieved after DPD processing. After aging, the grain size increased slightly together and there was an additional marginal decrease in the dislocation density. κ-carbides only appeared in the samples after DPD processing at the strain of 0.75 and after subsequent aging. Submicron-sized (Nb, Mo)C particles existed in the matrix before DPD and there was no change in size and distribution during DPD processing and post-DPD aging. The yield strengths of the steels after DPD at different strain rates increased significantly by ~120-190% compared with the as-received sample, where this is mainly due to a combination of dislocation strengthening and grain boundary strengthening. For the steel processed by DPD at strain of 0.75, there was an additional precipitation strengthening of κ-carbides besides the dislocation strengthening and grain boundary strengthening, and this produced an increase of over ~900 MPa in yield strength by comparison with the as-received steel. After aging, the yield strength decreased slightly due to a reduction in the dislocation density and a slight coarsening of the grains, except for samples after DPD at a strain of 0.75 which showed a slight increase in strength due to further κ precipitation. The strain rate strengthening effect and strain hardening ability were also analyzed.
Aging, Dynamic plastic deformation, Lightweight steels, Mechanical properties, Strengthening mechanisms
Li, Zongyuan
f2c3db30-8784-4a09-b2c2-fd963a56b255
Wang, Ying Chun
77cf014c-56e2-4569-bd19-ab2e86c4ae2c
Cheng, Xingwang
a6620e1f-2f98-42b8-a683-29b5bd2920d1
Gao, Chong
7139fc3a-f46c-4183-a41e-fa959d629951
Li, Zhuang
64327bd2-9cd2-49a3-a6fc-7e500f0769b7
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
26 January 2022
Li, Zongyuan
f2c3db30-8784-4a09-b2c2-fd963a56b255
Wang, Ying Chun
77cf014c-56e2-4569-bd19-ab2e86c4ae2c
Cheng, Xingwang
a6620e1f-2f98-42b8-a683-29b5bd2920d1
Gao, Chong
7139fc3a-f46c-4183-a41e-fa959d629951
Li, Zhuang
64327bd2-9cd2-49a3-a6fc-7e500f0769b7
Langdon, Terence G
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Li, Zongyuan, Wang, Ying Chun, Cheng, Xingwang, Gao, Chong, Li, Zhuang and Langdon, Terence G
(2022)
Microstructure and mechanical properties of an Fe–Mn–Al–C lightweight steel after dynamic plastic deformation processing and subsequent aging.
Materials Science and Engineering: A, 833, [142566].
(doi:10.1016/j.msea.2021.142566).
Abstract
An austenitic low-density steel was processed by dynamic plastic deformation (DPD) over the strain range from 0.25 to 0.75 followed by aging at 450°C and then it was subjected to compressive testing at strain rates of 1.0 × 10-3 − 2.0 × 103 s-1. The results show that fine grain structures with high density dislocations are achieved after DPD processing. After aging, the grain size increased slightly together and there was an additional marginal decrease in the dislocation density. κ-carbides only appeared in the samples after DPD processing at the strain of 0.75 and after subsequent aging. Submicron-sized (Nb, Mo)C particles existed in the matrix before DPD and there was no change in size and distribution during DPD processing and post-DPD aging. The yield strengths of the steels after DPD at different strain rates increased significantly by ~120-190% compared with the as-received sample, where this is mainly due to a combination of dislocation strengthening and grain boundary strengthening. For the steel processed by DPD at strain of 0.75, there was an additional precipitation strengthening of κ-carbides besides the dislocation strengthening and grain boundary strengthening, and this produced an increase of over ~900 MPa in yield strength by comparison with the as-received steel. After aging, the yield strength decreased slightly due to a reduction in the dislocation density and a slight coarsening of the grains, except for samples after DPD at a strain of 0.75 which showed a slight increase in strength due to further κ precipitation. The strain rate strengthening effect and strain hardening ability were also analyzed.
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More information
Accepted/In Press date: 24 December 2021
e-pub ahead of print date: 28 December 2021
Published date: 26 January 2022
Additional Information:
Funding Information:
The work was supported by the funding of National Science and Technology Major Project of China ( J2019-VI-0019-0134 ), the National Natural Science Foundation of China under Grant No. 51671030 and the European Research Council under Grant Agreement No. 267464-SPDMETALS (TGL).
Publisher Copyright:
© 2021 Elsevier B.V.
Keywords:
Aging, Dynamic plastic deformation, Lightweight steels, Mechanical properties, Strengthening mechanisms
Identifiers
Local EPrints ID: 454205
URI: http://eprints.soton.ac.uk/id/eprint/454205
ISSN: 0921-5093
PURE UUID: 7b503fe9-5802-47e1-8608-8ddebdf34acc
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Date deposited: 02 Feb 2022 17:46
Last modified: 17 Mar 2024 07:03
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Contributors
Author:
Zongyuan Li
Author:
Ying Chun Wang
Author:
Xingwang Cheng
Author:
Chong Gao
Author:
Zhuang Li
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