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

Journal article

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.

Authors: Huang, S; Luo, S; Qin, L; Shu, D; Sun, B

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Scripta Materialia
• Volume: 211
• Article number: 114484
• Publication date: 2022-01-09
• Acceptance date: 2021-12-21
• DOI: 10.1016/j.scriptamat.2021.114484
• ISSN: 1359-6462
• Language: English
• Keywords: FFR; empirical potential structure refinement; synchrotron x-ray total scattering; aluminium-scandium alloy; liquid atomic structure; in operando study of solidification