Pre-martensite and bainite reactions: A thermal stability study
The comparative analysis of two ways to achieve ultra-fine bainitic steels considering isothermal heat treatment above and below martensite start (Ms) temperature was formulated. Although the presence of pre-martensite below the Ms temperature accelerates the nucleation time of the bainitic transfor...
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Elsevier
2025-02-01
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| Series: | Materials & Design |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0264127525000413 |
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| author | Aleksandra Królicka José Antonio Jimenez Francisca G. Caballero |
| author_facet | Aleksandra Królicka José Antonio Jimenez Francisca G. Caballero |
| author_sort | Aleksandra Królicka |
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| description | The comparative analysis of two ways to achieve ultra-fine bainitic steels considering isothermal heat treatment above and below martensite start (Ms) temperature was formulated. Although the presence of pre-martensite below the Ms temperature accelerates the nucleation time of the bainitic transformation, the time to finish the transformation is longer (∼11.5 h) compared to the treatment above Ms (∼5 h). A qualitative and quantitative analysis of the morphology of the bainitic structure demonstrated that there are no significant differences in the thickness of the bainitic ferrite laths in both cases. However, a clear refinement of the retained austenite blocks of the steel treated below Ms was observed. Moreover, TEM and STEM/EDS studies revealed precipitation processes associated with the decomposition of the metastable bainitic and bainitic-martensitic structures during the tempering. It was shown that both heat treatment routes lead to secondary hardening during the tempering at 550 °C. At lower tempering temperatures, the bainitic matrix obtained above Ms was characterized by higher thermal stability, while the presence of pre-martensite in the steel treated below Ms has greater effectiveness in the secondary hardening effect at higher tempering temperatures and therefore in thermal stability of bainite at the high-temperature tempering range. These results provide a new perspective for designing heat treatment processes for advanced bainitic steels in applications subjected to operation at elevated temperatures. |
| format | Article |
| id | doaj-art-b8e3982ffd9446459853d1c0d17b5d76 |
| institution | Kabale University |
| issn | 0264-1275 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | Elsevier |
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| series | Materials & Design |
| spelling | doaj-art-b8e3982ffd9446459853d1c0d17b5d762025-01-22T05:40:58ZengElsevierMaterials & Design0264-12752025-02-01250113621Pre-martensite and bainite reactions: A thermal stability studyAleksandra Królicka0José Antonio Jimenez1Francisca G. Caballero2Wroclaw University of Science and Technology, Faculty of Mechanical Engineering, Department of Metal Forming, Welding and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wroclaw, Poland; Corresponding author.Department of Physical Metallurgy, National Center for Metallurgical Research (CENIM-CSIC), Avenida Gregorio del Amo, 8, 28040 Madrid, SpainDepartment of Physical Metallurgy, National Center for Metallurgical Research (CENIM-CSIC), Avenida Gregorio del Amo, 8, 28040 Madrid, SpainThe comparative analysis of two ways to achieve ultra-fine bainitic steels considering isothermal heat treatment above and below martensite start (Ms) temperature was formulated. Although the presence of pre-martensite below the Ms temperature accelerates the nucleation time of the bainitic transformation, the time to finish the transformation is longer (∼11.5 h) compared to the treatment above Ms (∼5 h). A qualitative and quantitative analysis of the morphology of the bainitic structure demonstrated that there are no significant differences in the thickness of the bainitic ferrite laths in both cases. However, a clear refinement of the retained austenite blocks of the steel treated below Ms was observed. Moreover, TEM and STEM/EDS studies revealed precipitation processes associated with the decomposition of the metastable bainitic and bainitic-martensitic structures during the tempering. It was shown that both heat treatment routes lead to secondary hardening during the tempering at 550 °C. At lower tempering temperatures, the bainitic matrix obtained above Ms was characterized by higher thermal stability, while the presence of pre-martensite in the steel treated below Ms has greater effectiveness in the secondary hardening effect at higher tempering temperatures and therefore in thermal stability of bainite at the high-temperature tempering range. These results provide a new perspective for designing heat treatment processes for advanced bainitic steels in applications subjected to operation at elevated temperatures.http://www.sciencedirect.com/science/article/pii/S0264127525000413Medium carbon bainitePre-martensiteRetained austeniteTempered bainite, secondary hardening |
| spellingShingle | Aleksandra Królicka José Antonio Jimenez Francisca G. Caballero Pre-martensite and bainite reactions: A thermal stability study Materials & Design Medium carbon bainite Pre-martensite Retained austenite Tempered bainite, secondary hardening |
| title | Pre-martensite and bainite reactions: A thermal stability study |
| title_full | Pre-martensite and bainite reactions: A thermal stability study |
| title_fullStr | Pre-martensite and bainite reactions: A thermal stability study |
| title_full_unstemmed | Pre-martensite and bainite reactions: A thermal stability study |
| title_short | Pre-martensite and bainite reactions: A thermal stability study |
| title_sort | pre martensite and bainite reactions a thermal stability study |
| topic | Medium carbon bainite Pre-martensite Retained austenite Tempered bainite, secondary hardening |
| url | http://www.sciencedirect.com/science/article/pii/S0264127525000413 |
| work_keys_str_mv | AT aleksandrakrolicka premartensiteandbainitereactionsathermalstabilitystudy AT joseantoniojimenez premartensiteandbainitereactionsathermalstabilitystudy AT franciscagcaballero premartensiteandbainitereactionsathermalstabilitystudy |