3D local atomic structure evolution in a solidifying Al-0.4Sc dilute alloy melt revealed in operando by synchrotron X-ray total scattering and modelling

Huang, Shi; Luo, Shifeng; Qin, Ling; Shu, Da; Sun, Baode; Lunt, Alexander J G; Korsunsky, Alexander M; Mi, Jiawei

Abstract

Using synchrotron X-ray total scattering and empirical potential structure refinement modelling, we studied systematically in operando condition the disorder-to-order local atomic structure transition in a pure Al and a dilute Al-0.4Sc alloy melt in the temperature range from 690 °C to 657 °C. In the liquid state, icosahedral short-range ordered Sc-centred Al polyhedrons form and most of them with Al coordination number of 10–12. As the melt is cooled to the semisolid state, the most Sc-centred polyhedrons become more connected atom clusters via vertex, edge and face-sharing. These polyhedrons exhibit partially icosahedral and partially face-centred-cubic symmetry. The medium-range ordered Sc-centred clusters with face-sharing are proved to be the “precursors” of the L12 Al3Sc primary phases in the liquid-solid coexisting state.

Citation

Huang, S., Luo, S., Qin, L., Shu, D., Sun, B., Lunt, A. J. G., …Mi, J. (2022). 3D local atomic structure evolution in a solidifying Al-0.4Sc dilute alloy melt revealed in operando by synchrotron X-ray total scattering and modelling. Scripta materialia, 211, Article 114484. https://doi.org/10.1016/j.scriptamat.2021.114484

• Journal Article Type: Article
• Acceptance Date: Dec 21, 2021
• Online Publication Date: Jan 9, 2022
• Publication Date: Apr 1, 2022
• Deposit Date: Apr 1, 2022
• Publicly Available Date: Apr 4, 2022
• Journal: Scripta Materialia
• Print ISSN: 1359-6462
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 211
• Article Number: 114484
• DOI: https://doi.org/10.1016/j.scriptamat.2021.114484
• Keywords: Aluminium-Scandium alloy, Synchrotron X-ray total scattering; Empirical Potential Structure Refinement; Liquid Atomic Structure; In Operando Study of Solidification
• Public URL: https://hull-repository.worktribe.com/output/3910489