Faceted-nonfaceted growth transition and 3-D morphological evolution of primary Al_6Mn microcrystals in directionally solidified Al-3 at.% Mn alloy
Faceted-nonfaceted growth transition and 3-D morphological evolution of primary Al_6Mn microcrystals in directionally solidified Al-3 at.% Mn alloy
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DOI：
10.1557/jmr.2014.111
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发表时间：
2014-06
影响因子：
2.7
通讯作者：
Huijun Kang;Tongmin Wang;Xinzhong Li;Yan-Qing Su;Jingjie Guo;H. Fu
中科院分区：
文献类型：
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作者：
Huijun Kang;Tongmin Wang;Xinzhong Li;Yan-Qing Su;Jingjie Guo;H. Fu
全面了解凝固过程中金属间化合物（IMC）的生长模式对于晶体生长理论及其性能优化至关重要。在本文中，研究了定向凝固 Al-3 at.% Mn 合金在宽范围的生长速率下初生 Al_6Mn IMC 的生长模式和三维 (3D) 形貌。随着生长速率的增加，观察到从刻面 (100 µm/s) 的转变。相应地，初生Al_6Mn的3D形貌从实心多面体转变为空心结构，然后转变为枝晶。这种变化与Al_6Mn的晶体各向异性和生长动力学决定的不同晶面的竞争生长有关。提出了基于原子团簇附着的生长模型来揭示生长转变，并利用不同晶面之间的生长速率比来适当地揭示低速率下不同形貌的形成机制。
A comprehensive understanding of the growth pattern of intermetallic compounds (IMCs) during solidification is critical to both the crystal-growth theory and its property optimization. In this article, growth pattern and three-dimensional (3D) morphology of primary Al_6Mn IMC were investigated in directionally solidified Al-3 at.% Mn alloy at a wide range of growth rates. A transition from faceted (100 µm/s) was observed with increasing growth rates. Correspondingly, 3D morphologies of primary Al_6Mn change from a solid polyhedron to a hollow structure, and then to a dendrite. This kind of change is associated with the competitive growths of different crystal planes determined by the crystallographic anisotropy and growth kinetics of Al_6Mn. A growth model based on atomic cluster attachment is proposed to reveal the growth transition, and a growth-rate ratio between different crystal planes is used to appropriately reveal the formation mechanism of different morphologies at low rates.