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

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

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish
Article number114484
JournalScripta Materialia
DOIs
Publication statusPublished - 2022
Externally publishedYes

Keywords

  • Aluminium-Scandium alloy, Synchrotron X-ray total scattering
  • Empirical Potential Structure Refinement
  • In Operando Study of Solidification
  • Liquid Atomic Structure

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