A crystalline aggregate with icosahedral symmetry: Implication for the crystallography of twinning and grain boundaries
A crystalline aggregate with icosahedral symmetry: Implication for the crystallography of twinning and grain boundaries
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具有二十面体对称性的晶体聚集体：对孪晶和晶界晶体学的影响
DOI：
10.1080/13642818908209746
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
D. Gratias
中科院分区：
文献类型：
--
作者：
L. Bendersky;J. Cahn;D. Gratias
摘要在快速凝固Al-Mn-Fe-Si合金中发现了具有二十面体对称性的多晶聚集体。晶体之间的取向关系是使得所有晶体中的二十面体图案是平行的。虽然立方轴绕无理轴π 1，τ，0 π旋转五次，但在数百个晶体中只有五个取向。这是一种特殊的取向关系，但既不存在重合，也不存在孪晶点阵（S = σ = ∞）。重新审视了孪晶和特殊晶界的概念，提出了一种基于减少算术独立晶格矢量数目的特殊取向（超孪晶）的新定义。它包含了新老的特殊取向，并且可以很容易地用准晶格来解释。
Abstract Polycrystalline aggregates with overall icosahedral symmetry have been found in rapidly solidified Al—Mn—Fe—Si alloys. The orientation relationship between crystals is such that icosahedral motifs in all the crystals are parallel. Although the cubic axes undergo fivefold rotation about irrational 〈1, τ, 0〉 axes, only five orientations occur among hundreds of crystals. This is a special orientation relationship, but there is neither a coincidence nor a twin lattice (S = σ = ∞). The concepts of twinning and special grain boundaries are re-examined, and a new definition of special orientations (hypertwins) based on the reduction of the number of arithmetically independent lattice vectors is proposed. It includes both old and new special orientations and can be easily interpreted in terms of quasilattices.