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
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
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DOI：
10.1016/j.scriptamat.2021.114484
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发表时间：
2022-01
影响因子：
6
通讯作者：
Shih-Chang Huang;S. Luo;L. Qin;D. Shu;Bao-de Sun;A. Lunt;A. Korsunsky;J. Mi
中科院分区：
文献类型：
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作者：
Shih-Chang Huang;S. Luo;L. Qin;D. Shu;Bao-de Sun;A. Lunt;A. Korsunsky;J. Mi
利用同步加速器 X 射线全散射和经验势结构细化建模，我们在操作条件下系统地研究了纯 Al 和稀 Al-0.4Sc 合金熔体在 690 °C 至 657 °C 温度范围内从无序到有序的局部原子结构转变。在液态下，形成二十面体短程有序的Sc中心Al多面体，其中大多数Al配位数为10-12。当熔体冷却到半固态时，大多数以钪为中心的多面体通过共享顶点、边和面而变得更加连接的原子簇。这些多面体表现出部分二十面体和部分面心立方对称性。共面的中程有序Sc中心团簇被证明是液固共存状态下L12Al3Sc初生相的“前体”。
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 orderedSc-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 mostSc-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 orderedSc-centred clusters with face-sharing are proved to be the “precursors” of the L12Al3Sc primary phases in the liquid-solid coexisting state.