Ab initio thermodynamics of complex alloys: The case of Al- and Mn-doped ferritic steels

In the context of Al- and Mn-doped ferritic steels, we progressively elaborate an atomic-scale energy model to reproduce the thermodynamic behaviour of quaternary Fe-Al-Mn-C on a bcc lattice. This model is built on physical concepts: DEC calculations, pair Hamiltonians, non-configurational thermal effects, these elements being combined in a reasoned way to lead to a mastered and predictive formulation. In particular, this approach allows to explore the correlation between ordering in substitutional ternary Fe-Al-Mn and interstitial carbon, which brings new elements to the metallurgy of carbon in ferritic steels. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.