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MM: Fachverband Metall- und Materialphysik

MM 13: Phase Transformations I

MM 13.1: Vortrag

Montag, 18. März 2024, 15:45–16:00, C 230

Impact of magneto-chemical coupling on phase stability, vacancy formation and atomic diffusion in Fe-Cr alloys — •Hilal Bozkurt¹, Chu-Chun Fu¹, and Cyrille Barreteau² — ¹Université Paris-Saclay, CEA, Service de recherche en Corrosion et Comportement des Matériaux, SRMP, 91191 Gif sur Yvette, France — ²CEA, CNRS, SPEC, Gif-sur-Yvette, France

High chromium ferritic steels present a large variety of technological applications. For instance, they are promising candidate as structural materials for future fusion reactors, thanks to their strong resistance to corrosion and to radiation damage. On the other side, it is known from numerous studies that thermodynamic and kinetic properties of Fe-Cr alloys are highly sensitive to magnetism.

Despite the large amount of previous theoretical and experimental efforts, the impact of magnetism on vacancy formation and vacancy-mediated diffusion in Fe-Cr as a function of temperature and alloy composition is still unclear.

In this work, we first investigate the dependency of vacancy formation energy and migration barriers on the magnetic and chemical configuration of Fe-Cr alloys, via first principles calculations. The obtained data are then used to parameterize a spin-atomic Monte Carlo model, in order to perform simulations for an accurate prediction of equilibrium vacancy concentration and vacancy-mediated atomic-diffusion coefficients versus temperature. The specificity of the present model consists in an explicit treatment of both chemical and magnetic variables, which enables to elucidate the impact of the magneto-chemical interplay on the studied properties.

Keywords: simulations; Fe-Cr alloys; magnetism; diffusion; diagram