Abstract Based on the first-principles calculations and crystallographic anisotropy analysis, the effect of additional solute elements on the dendritic growth behavior of binary Mg-X (X = Al, Ca, Y, Ba, Sn, Gd and Zn) alloys are investigated in terms of the orientation-dependent surface energy. The preferred growth direction of the α-Mg dendrite is found to be dependent on the magnitude of the anisotropic surface energy and the difference of crystallographic anisotropy between the matrix Mg and the additional solute X. The most densely packed crystallographic planes are found to be the energetically favorable planes with the minimum surface energy, as exemplified by the { 111 } plane of Al with fcc (face-centered cubic) structure, the { 110 } plane of Ba with bcc (body-centered cubic) structure, and the { 0001 } plane of Y with hcp (hexagonal-close packed) structure. For all additional solute elements studied, Zn exhibits the maximum anisotropy and the according effect on the growth behavior of the α-Mg dendrite is the most significant, which could also be reflected by the complex growth patterns of the Mg-Zn alloy dendrite observed in experiments. Compared with Zn, the crystallographic anisotropy of the other additional solutes is weaker, and their effect on the α-Mg dendrite growth is not as significant as Zn, which is reflected by their similar eighteen-primary branch dendritic morphology in 3D.

中文翻译：

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额外的溶质元素（X= Al、Ca、Y、Ba、Sn、Gd 和 Zn）对镁合金枝晶生长过程中结晶各向异性的影响

摘要 基于第一性原理计算和晶体各向异性分析，研究了添加溶质元素对二元 Mg-X（X = Al、Ca、Y、Ba、Sn、Gd 和 Zn）合金枝晶生长行为的影响。依赖于取向的表面能的术语。发现 α-Mg 枝晶的优选生长方向取决于各向异性表面能的大小以及基体 Mg 和附加溶质 X 之间结晶各向异性的差异。发现最密集的结晶平面是具有最小表面能的能量有利平面，例如具有 fcc（面心立方）结构的 Al 的 {111} 平面，具有 bcc（体心立方）结构的 Ba 的 {110} 平面，和具有 hcp（六边形密堆积）结构的 Y 的 {0001} 平面。对于所有研究的附加溶质元素，Zn 表现出最大的各向异性，并且对 α-Mg 枝晶生长行为的相应影响最显着，这也可以通过观察到的 Mg-Zn 合金枝晶的复杂生长模式反映出来。实验。与 Zn 相比，其他附加溶质的晶体各向异性较弱，它们对 α-Mg 枝晶生长的影响不如 Zn 显着，这体现在它们在 3D 中相似的十八主枝枝晶形貌。这也可以通过实验中观察到的 Mg-Zn 合金枝晶的复杂生长模式反映出来。与 Zn 相比，其他附加溶质的晶体各向异性较弱，它们对 α-Mg 枝晶生长的影响不如 Zn 显着，这体现在它们在 3D 中相似的十八主枝枝晶形貌。这也可以通过实验中观察到的 Mg-Zn 合金枝晶的复杂生长模式反映出来。与 Zn 相比，其他附加溶质的晶体各向异性较弱，它们对 α-Mg 枝晶生长的影响不如 Zn 显着，这体现在它们在 3D 中相似的十八主枝枝晶形貌。