Microstructure and tensile behaviors for a medium Mn steel with δ-ferrite phase under different annealing temperatures
In this experiment, we systematically investigated the microstructure evolution, mechanical properties, and deformation behaviors as functions of annealing temperature using cold-rolled Fe-0.05C–6Mn–1Al-1.5Si steel. Almost all annealed specimens are composed of the equiaxed and granular α-ferrite (α...
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doaj-1d1ebc3ec0914979a63bb175e666ed622021-08-28T04:46:23ZengElsevierJournal of Materials Research and Technology2238-78542021-11-0115708718Microstructure and tensile behaviors for a medium Mn steel with δ-ferrite phase under different annealing temperaturesTianle Li0Shu Yan1Xianghua Liu2Department of Plasticity Technology, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, ChinaSchool of Materials Science and Engineering, Northeastern University, Shenyang, 110819, China; Corresponding author.School of Materials Science and Engineering, Northeastern University, Shenyang, 110819, ChinaIn this experiment, we systematically investigated the microstructure evolution, mechanical properties, and deformation behaviors as functions of annealing temperature using cold-rolled Fe-0.05C–6Mn–1Al-1.5Si steel. Almost all annealed specimens are composed of the equiaxed and granular α-ferrite (α) grains due to recrystallization, reversed austenite (γ) grains because of reversed transformation from deformed martensite, and fibrous δ-ferrite (δ) grains only undergoing recovery during intercritical annealing except for 760 °C. It is interesting that several annealing twins are formed within γ grains. The outstanding combination of strength and ductility is obtained for annealing at 740 °C. The tensile strength and total elongation are 980 MPa and 32.1%, which are attributed to the ultrafine grains and optimal TRIP effect associated with rational γ content and stability. A phenomenon that yield point elongation (YPE) gradually shortens with increased γ content and decreased γ stability is observed. What's more, the mechanism that active α′ formation can promote the improvement of work hardening rate and further curtail YPE is verified using deep-cryogenic treatment. Based on SEM observation, microscopic strain of δ grains appears nearly consistent with matrix (α and γ grains) during tensile process, although δ phase presents as fibrous morphology with coarse size.http://www.sciencedirect.com/science/article/pii/S2238785421008929Medium Mn steelAnnealing temperatureMicrostructureMechanical propertyYield point elongation |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Tianle Li Shu Yan Xianghua Liu |
spellingShingle |
Tianle Li Shu Yan Xianghua Liu Microstructure and tensile behaviors for a medium Mn steel with δ-ferrite phase under different annealing temperatures Journal of Materials Research and Technology Medium Mn steel Annealing temperature Microstructure Mechanical property Yield point elongation |
author_facet |
Tianle Li Shu Yan Xianghua Liu |
author_sort |
Tianle Li |
title |
Microstructure and tensile behaviors for a medium Mn steel with δ-ferrite phase under different annealing temperatures |
title_short |
Microstructure and tensile behaviors for a medium Mn steel with δ-ferrite phase under different annealing temperatures |
title_full |
Microstructure and tensile behaviors for a medium Mn steel with δ-ferrite phase under different annealing temperatures |
title_fullStr |
Microstructure and tensile behaviors for a medium Mn steel with δ-ferrite phase under different annealing temperatures |
title_full_unstemmed |
Microstructure and tensile behaviors for a medium Mn steel with δ-ferrite phase under different annealing temperatures |
title_sort |
microstructure and tensile behaviors for a medium mn steel with δ-ferrite phase under different annealing temperatures |
publisher |
Elsevier |
series |
Journal of Materials Research and Technology |
issn |
2238-7854 |
publishDate |
2021-11-01 |
description |
In this experiment, we systematically investigated the microstructure evolution, mechanical properties, and deformation behaviors as functions of annealing temperature using cold-rolled Fe-0.05C–6Mn–1Al-1.5Si steel. Almost all annealed specimens are composed of the equiaxed and granular α-ferrite (α) grains due to recrystallization, reversed austenite (γ) grains because of reversed transformation from deformed martensite, and fibrous δ-ferrite (δ) grains only undergoing recovery during intercritical annealing except for 760 °C. It is interesting that several annealing twins are formed within γ grains. The outstanding combination of strength and ductility is obtained for annealing at 740 °C. The tensile strength and total elongation are 980 MPa and 32.1%, which are attributed to the ultrafine grains and optimal TRIP effect associated with rational γ content and stability. A phenomenon that yield point elongation (YPE) gradually shortens with increased γ content and decreased γ stability is observed. What's more, the mechanism that active α′ formation can promote the improvement of work hardening rate and further curtail YPE is verified using deep-cryogenic treatment. Based on SEM observation, microscopic strain of δ grains appears nearly consistent with matrix (α and γ grains) during tensile process, although δ phase presents as fibrous morphology with coarse size. |
topic |
Medium Mn steel Annealing temperature Microstructure Mechanical property Yield point elongation |
url |
http://www.sciencedirect.com/science/article/pii/S2238785421008929 |
work_keys_str_mv |
AT tianleli microstructureandtensilebehaviorsforamediummnsteelwithdferritephaseunderdifferentannealingtemperatures AT shuyan microstructureandtensilebehaviorsforamediummnsteelwithdferritephaseunderdifferentannealingtemperatures AT xianghualiu microstructureandtensilebehaviorsforamediummnsteelwithdferritephaseunderdifferentannealingtemperatures |
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