Impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low- and medium-C carbide-free bainitic steels
This work aims to describe the microstructural evolution of bainite during continuous cooling from austenite with varying grain size, morphology and defect density in two carbide-free bainitic steels with low and medium C contents. To achieve these conditions, hot and warm deformations were applied,...
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Elsevier
2025-09-01
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| Series: | Materials & Design |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127525008536 |
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| author | Pedro José de Castro Antonio Carlos de Figueiredo Silveira Alexandre da Silva Rocha Andreas Stark Thomas Sourmail Jérémy Epp |
| author_facet | Pedro José de Castro Antonio Carlos de Figueiredo Silveira Alexandre da Silva Rocha Andreas Stark Thomas Sourmail Jérémy Epp |
| author_sort | Pedro José de Castro |
| collection | DOAJ |
| description | This work aims to describe the microstructural evolution of bainite during continuous cooling from austenite with varying grain size, morphology and defect density in two carbide-free bainitic steels with low and medium C contents. To achieve these conditions, hot and warm deformations were applied, and compared to an undeformed condition. Thermomechanical treatments were performed with a dilatometer and monitored in-situ via high-energy X-Ray diffraction. EBSD was employed for identifying the variant pairing behaviour and misorientation distributions. In comparison to the undeformed condition, a delay in the transformation kinetics was observed for the deformed conditions of both steels. The delay was correlated to the dislocation density of austenite before the onset of the bainitic transformation. Due to the delay, the bainite transformation temperature was lower in the deformed conditions. In spite of this, there was an increase in the frequency of low-angle misorientation boundaries as given by the misorientation distributions. This effect is unexpected in view of established thermodynamic models for prediction of the bainite morphology. This discrepancy was attributed to the substructure introduced by the deformation, which was inherited by bainite. A microstructure evolution history was proposed based on the concurring metallurgical phenomena during the deformation and subsequent continuous cooling. |
| format | Article |
| id | doaj-art-e71be77093a249b080e720135ce3e2aa |
| institution | Kabale University |
| issn | 0264-1275 |
| language | English |
| publishDate | 2025-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Materials & Design |
| spelling | doaj-art-e71be77093a249b080e720135ce3e2aa2025-08-20T03:58:11ZengElsevierMaterials & Design0264-12752025-09-0125711443310.1016/j.matdes.2025.114433Impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low- and medium-C carbide-free bainitic steelsPedro José de Castro0Antonio Carlos de Figueiredo Silveira1Alexandre da Silva Rocha2Andreas Stark3Thomas Sourmail4Jérémy Epp5Leibniz Institute for Materials Engineering-IWT, Badgasteiner Str. 3, 28359 Bremen, Germany; Corresponding author.Leibniz Institute for Materials Engineering-IWT, Badgasteiner Str. 3, 28359 Bremen, GermanyMetal Forming Laboratory-LdTM, Av. Bento Gonçalves 9500, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, BrazilHelmholtz-Zentrum Hereon, Institute of Materials Physics, Max-Planck-Straße 1, 21503 Geesthacht, GermanyArcelorMittal, Voie Romaine, 57280 Maizières-lès-Metz, FranceLeibniz Institute for Materials Engineering-IWT, Badgasteiner Str. 3, 28359 Bremen, Germany; MAPEX Centre for Materials and Processes, University of Bremen, Bibliothekstraße 1, 28359 Bremen, GermanyThis work aims to describe the microstructural evolution of bainite during continuous cooling from austenite with varying grain size, morphology and defect density in two carbide-free bainitic steels with low and medium C contents. To achieve these conditions, hot and warm deformations were applied, and compared to an undeformed condition. Thermomechanical treatments were performed with a dilatometer and monitored in-situ via high-energy X-Ray diffraction. EBSD was employed for identifying the variant pairing behaviour and misorientation distributions. In comparison to the undeformed condition, a delay in the transformation kinetics was observed for the deformed conditions of both steels. The delay was correlated to the dislocation density of austenite before the onset of the bainitic transformation. Due to the delay, the bainite transformation temperature was lower in the deformed conditions. In spite of this, there was an increase in the frequency of low-angle misorientation boundaries as given by the misorientation distributions. This effect is unexpected in view of established thermodynamic models for prediction of the bainite morphology. This discrepancy was attributed to the substructure introduced by the deformation, which was inherited by bainite. A microstructure evolution history was proposed based on the concurring metallurgical phenomena during the deformation and subsequent continuous cooling.http://www.sciencedirect.com/science/article/pii/S0264127525008536Thermomechanical processingSynchrotron diffractionBainitic steelContinuous coolingCarbide-free bainiteMechanical stabilization |
| spellingShingle | Pedro José de Castro Antonio Carlos de Figueiredo Silveira Alexandre da Silva Rocha Andreas Stark Thomas Sourmail Jérémy Epp Impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low- and medium-C carbide-free bainitic steels Materials & Design Thermomechanical processing Synchrotron diffraction Bainitic steel Continuous cooling Carbide-free bainite Mechanical stabilization |
| title | Impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low- and medium-C carbide-free bainitic steels |
| title_full | Impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low- and medium-C carbide-free bainitic steels |
| title_fullStr | Impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low- and medium-C carbide-free bainitic steels |
| title_full_unstemmed | Impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low- and medium-C carbide-free bainitic steels |
| title_short | Impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low- and medium-C carbide-free bainitic steels |
| title_sort | impact of hot and warm deformation on the bainite morphology and kinetics during continuous cooling of low and medium c carbide free bainitic steels |
| topic | Thermomechanical processing Synchrotron diffraction Bainitic steel Continuous cooling Carbide-free bainite Mechanical stabilization |
| url | http://www.sciencedirect.com/science/article/pii/S0264127525008536 |
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