ALLAIN, Sébastien; GEANDIER, Guillaume; HELL, Jean-Christophe; SOLER, Michel; DANOIX, Fréderic; GOUNÉ, Mohamed

doi:10.3390/met7070232

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http://creativecommons.org/licenses/by-nc-nd/

ALLAIN, Sébastien
Institut Jean Lamour [IJL]

GEANDIER, Guillaume
Institut Jean Lamour [IJL]

HELL, Jean-Christophe
ArcelorMittal Maizières Research SA

Langue

Article de revue

Ce document a été publié dans

Metals. 2017, vol. 7, n° 7, p. 232

MDPI

Résumé en anglais

We report the first ultra-fast time-resolved quantitative information on the quenching and partitioning process of conventional high-strength steel by an in situ high-energy X-ray diffraction (HEXRD) experiment. The time and temperature evolutions of phase fractions, their carbon content, and internal stresses were determined and discussed for different process parameters. It is shown that the austenite-to-martensite transformation below the martensite start temperature Ms is followed by a stage of fast carbon enrichment in austenite during isothermal holding at both 400 and 450 °C. The analysis proposed supports the concurrent bainite transformation and carbon diffusion from martensite to austenite as the main mechanisms of this enrichment. Furthermore, we give evidence that high hydrostatic tensile stresses in austenite are produced during the final quenching, and must be taken into account for the estimation of the carbon content in austenite. Finally, a large amount of carbon is shown to be trapped in the microstructure.< Réduire

Mots clés en anglais

steel

martensite

bainite

Q&P

synchrotron

HEXRD

TRIP

DOI

http://dx.doi.org/10.3390/met7070232

Project ANR

Partition du carbone dans les phases ferritiques nanostructurées: cinétiques et microstructures - ANR-14-CE07-0029
Design des Alliages Métalliques pour Allègement des Structures - ANR-11-LABX-0008

Origine

Importé de hal

Unités de recherche

Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) - UMR 5026