A Stable Decagonal Quasicrystal in the Al–Cu–Co System

An Pang Tsai, Akihisa Inoue, Tsuyoshi Masumoto

    Research output: Contribution to journalArticlepeer-review

    123 Citations (Scopus)


    The structure and growth morphology of Al65Cu15Fe20−xCox and Al65Cu20Fe15−xCox alloys have been examined in rapidly solidified, conventionally solidified and fully annealed states. A conventionally solidified Al65Cu15Co20 alloy, which was prepared by the whole substitution of Fe by Co for a stable icosahedral Al65Cu20Fe15 quasicrystal, was found to consist of a stable decagonal quasicrystal with a columnar morphology. The length of the decagonal column is as large as about 0.15 mm and the growth is thought to take place along a preferential direction parallel to the tenfold periodic axis because the plane perpendicular to the longitudinal direction of the column has the morphology of five dendrite arms radiating from the dendrite centers. The finding of the stable decagonal quasicrystal is important in the clarification of the formation mechanism and fundamental properties of the quasicrystals with an icosahedral or a decagonal structure.

    Original languageEnglish
    Pages (from-to)300-304
    Number of pages5
    JournalMaterials Transactions, JIM
    Issue number4
    Publication statusPublished - 1989 Jan 1


    • aluminum-copper-cobalt
    • annealed ingot
    • columnar growth morphology
    • decagonal phase
    • five dendrite arms
    • stable quasicrystal
    • tenfold symmetry
    • two-dimensional quasicrystal

    ASJC Scopus subject areas

    • Engineering(all)


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