Accéder directement au contenu Accéder directement à la navigation
Article dans une revue

Revisiting the formation mechanism of intragranular κ-carbide in austenite of a Fe-Mn-Al-Cr-C low-density steel

Abstract : It was usually believed that the formation of intragranular κ-carbide in γ-austenite was attributed to spinodal decomposition followed by ordering reaction. In this work, near-atomic scale characterization of an austenite-based Fe-20Mn-9Al-3Cr-1.2C (wt. %) low-density steel, using (high-resolution) scanning transmission electron microscopy and atomic probe tomography, reveals that the initially-formed κ-carbides (2-3 nm in particle size) are featured with an ordered L′12 structure but without detectable chemical partitioning. The Gibbs energy of the FCC phase obtained by thermodynamic calculations always shows a positive curvature (i.e. d2g/dx2< 0) with the variable contents of Al and C in the temperature range 400-800 °C. Both the results demonstrate that the ordered nuclei of κ-carbide can form directly in the disordered γ-austenite rather than through the well-known spinodal decomposition-ordering mechanism. The extremely low nucleation barrier is due to the similar lattice structure, same composition and complete coherency between the γ-austenite matrix and κ-carbides.
Type de document :
Article dans une revue
Liste complète des métadonnées

https://hal.univ-lille.fr/hal-03167683
Contributeur : Lilloa Université de Lille <>
Soumis le : vendredi 12 mars 2021 - 12:09:33
Dernière modification le : samedi 13 mars 2021 - 03:33:35

Identifiants

Collections

Citation

Jianlei Zhang, Yueshan Jiang, Weisen Zheng, Yuxiang Liu, Ahmed Addad, et al.. Revisiting the formation mechanism of intragranular κ-carbide in austenite of a Fe-Mn-Al-Cr-C low-density steel. Scripta Materialia, 2021, Scripta Materialia, 199, pp.113836. ⟨10.1016/j.scriptamat.2021.113836⟩. ⟨hal-03167683⟩

Partager

Métriques

Consultations de la notice

68