ALLAIN, Sébastien Yves Pierre; GAUDEZ, Steve; GEANDIER, Guillaume; HELL, Jean-Christophe; GOUNÉ, Mohamed; DANOIX, Fréderic; SOLER, Michel; AOUED, Samy; POULON-QUINTIN, Angeline

doi:10.1016/j.msea.2017.10.105

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ALLAIN, Sébastien Yves Pierre
Institut Jean Lamour [IJL]

GAUDEZ, Steve
Institut Jean Lamour [IJL]

GEANDIER, Guillaume
Institut Jean Lamour [IJL]

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Article de revue

Ce document a été publié dans

Materials Science and Engineering: A. 2018-01, vol. 710, p. 245-250

Elsevier

Résumé en anglais

Quenching and Partitioning (Q&P) process permits to produce innovative microstructures containing large fraction of carbon enriched retained austenite. The present study highlights that austenite undergoes significant internal stresses generated during such thermal cycle. Both mechanical and chemical contributions are likely to affect its stability at room temperature and thus the resulting mechanical properties of the steel. The experiments carried out by High Energy X-Ray Diffraction (HEXRD) show unambiguously that internal stresses in austenite originate from martensitic transformation strain and from additional hydrostatic stresses induced during both reheating to partitioning temperature and final cooling. These eigenstrains are attributed to the difference in Coefficients of Thermal Expansion (CTE) between martensite and austenite and are predicted successfully with a purely elastic mean field approach. In the present study, retained austenite is shown to be in compression at room temperature. As a consequence, this state of stress contributes to stabilize retained austenite against a possible strain induced transformation at room temperature and affects the way to determine the carbon content in austenite.< Réduire

Mots clés en anglais

Steels

Q&P

Synchrotron

Internal stresses

Austenite

Martensite

DOI

http://dx.doi.org/10.1016/j.msea.2017.10.105

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