Skip to Main content Skip to Navigation

Thermodynamique de nouvelles solutions d'aciers de 3ème génération à structure duplex

Abstract : A third generation of Fe-Mn-Al-C steels with a duplex structure, for Mn and Al contents less than 8%mass, could be a promising response to the 20% weight lightening of automotive vehicles, by keeping a high strength and a high formability.The knowledge of the corresponding quaternary phase diagram serves as a roadmap for the choice of compositions and the optimization of elaboration conditions. A reliable and precise thermodynamic database is therefore required. However, the literature data on the Fe-Mn-Al-C quaternary system in the targeted domains are limited.This study is devoted to the establishment of phase equilibria involving ferrite-α, austenite-γ and carbide-κ (Fe,Mn)3AlC between 700 and 1000°C by a coupled approach of experiments and thermodynamic modeling. A kinetic model (DICTRA) is proposed to support the experimental evolution of phase fraction and composition. The kinetics of austenite formation as a function of the alloy composition and of the maintaining temperature in the intercritical domain have been calculated. The phases in equilibrium, characterized by XRD, SEM, EPMA, are represented as α/γ, γ/κ, α/γ/κ tie-lines in order to specify the stability fields of γ and κ. These data are used to refine the thermodynamic description of the quaternary system but it is necessary to revise the modeling of κ carbide.
Complete list of metadatas
Contributor : Abes Star :  Contact
Submitted on : Thursday, June 21, 2018 - 2:12:14 AM
Last modification on : Wednesday, October 7, 2020 - 1:16:03 PM
Long-term archiving on: : Monday, September 24, 2018 - 11:28:37 AM


Version validated by the jury (STAR)


  • HAL Id : tel-01819772, version 1



Aurore Mestrallet. Thermodynamique de nouvelles solutions d'aciers de 3ème génération à structure duplex. Mécanique des matériaux [physics.class-ph]. Université Grenoble Alpes, 2017. Français. ⟨NNT : 2017GREAI075⟩. ⟨tel-01819772⟩



Record views


Files downloads