Planar defect in approximant: the case of Cu-Al-Sc alloy

ABSTRACT

The {110} planar defect formed in the Cu-Al-Sc 1/1 approximant has been studied by means of electron microscopy and 6-dimensional analysis. As the displacement vector of the planar defect, $1/2〈\tau ,{\tau }^{-1},0〉$ has been proposed. Here τ denotes the golden ratio. This vector corresponds to a 6-dimensional translation of type [111000] and also to the c-linkage of Tsai-type clusters. An atomic structure model of the planar defect has been constructed referring to the structural properties of the regular 1/1 approximant; namely truncated triacontahedron framework and embedded clusters. This structural model was validated by the agreement between the observed and simulated HAADF-STEM images. Models of the intersection of two planar defects and the triple point, where three planar defects intersect, were also proposed. All local structures formed at these defects are understood by the concept of so-called canonical cell tiling.

KEYWORDS:

• Approximants
• planar defects
• quasicrystals
• electron microscopy
• Tsai-type
• Cu-based

Acknowledgement

Part of the experiments was conducted in collaboration with T. Honma and A. Hirao. The aperture for dark-field imaging of Figure 7 was prepared with the help of H. Takakura. The authors appreciate their cooperation. They also thank T. Hiroto for providing useful information. Synchrotron radiation experiments were performed at SPring-8 BL02B2 with the approval of the Japan Synchrotron Radiation Research Institute (No. 2008B1255).

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No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

Y.-G.S was supported by the Ministry of Education Culture Sports Science and Technology, Japan, grant number JPMXP09A18UT0198. T.I. was supported by the Japan Society for the Promotion of Science, grant number 19H05818. M.M. was supported by the Slovak Research and Development Agency (grant number APVV-19-0369).