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MM: Fachverband Metall- und Materialphysik
MM 3: Topical Session: Sustainable metallurgy
MM 3.6: Talk
Monday, March 18, 2024, 12:00–12:15, C 130
Multi-technique investigation of Fe-rich intermetallic compounds for more impurity-tolerant Al alloys — •Shikang Feng1, Yilun Gong2, Jörg Neugebauer2, Dierk Raabe2, Enzo Liotti1, and Patrick S. Grant1 — 1University of Oxford, UK — 2Max-Planck-Institut für Eisenforschung GmbH, Germany
During Al alloy solidification, Fe impurities precipitate as coarse (up to millimetres), anisotropic Fe-rich intermetallic compounds (IMCs), severely undermining tensile ductility and toughness, hindering Al recycling. Increasing effort is made to understanding the formation and growth of these IMCs, for a better control of their type, morphology, size and distribution for more sustainable, impurity-tolerant Al recycling processes. In this work, we use in situ synchrotron X-ray radiography to study systematically the formation and growth kinetics of Al13Fe4 in a model Al-3wt.%Fe alloy, at cooling rates 0.5-20 Ks−1, representative of industrial conditions. These are then combined with post-solidification electron backscattered diffraction, X-ray computed tomography and atomic-resolution scanning transmission electron microscopy to elaborate on the role of twinning in Al13Fe4 formation and growth mechanisms. Finally, we show how we fuse the multi-technique insights to control the size and morphology of otherwise coarse, plate-like Al13Fe4 using twinning-based modification. The role of targeted alloying additions in the modification and their interplay with twin boundaries is rationalised by density functional theory calculations and atomistic simulations. The work paves a potential pathway to designing next-generation, impurity-tolerant recycled Al alloys.
Keywords: Synchrotron X-ray imaging; Phase transformation; High-resolution characterisations; Computational Materials Modelling; aluminium alloys