Title :

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

Author(s) :

Zhang, Jianlei [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Shanghai University
Jiang, Yueshan [Auteur]
Shanghai University
Zheng, Weisen [Auteur]
Shanghai University
Liu, Yuxiang [Auteur]
Shanghai University
Addad, Ahmed [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Ji, Gang [Auteur]
Unité Matériaux et Transformations - UMR 8207 [UMET]
Song, Changjiang [Auteur]
Shanghai University
Zhai, Qijie [Auteur]
Shanghai University

Journal title :

Scripta Materialia

Abbreviated title :

Scripta Materialia

Volume number :

199

Pages :

113836

Publisher :

Elsevier BV

Publication date :

2021-07-01

ISSN :

1359-6462

English keyword(s) :

Low-density steel
κ-carbide
Spinodal decomposition
Atom probe tomography (APT)
Transmission electron microscopy (TEM)

HAL domain(s) :

Chimie/Matériaux
Chimie/Polymères

English abstract : [en]

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 ...
Show more >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.Show less >

Language :

Anglais

Audience :

Non spécifiée

Administrative institution(s) :

Université de Lille
CNRS
INRA
ENSCL

Collections :

• Unité Matériaux et Transformations (UMET) - UMR 8207

Research team(s) :

Métallurgie Physique et Génie des Matériaux

Submission date :

2021-03-12T09:02:10Z
2021-03-12T11:09:23Z