Vacancy ordered phases and one-dimensional quasiperiodicity

Chattopadhyay, K.; Lele, S.; Thangaraj, N.; Ranganathan, S.

doi:10.1016/0001-6160(87)90197-0

Cited by 90 publications

(28 citation statements)

References 16 publications

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“…In agreement with the data available in literature at the present time for the alloys Al±Cu±Fe [7], Al±Ni [8], Al±Cu±Ni [9], and Al±Cu±Co [10] there is a concentration short-range order realized in the b-phase near the specified compositions, and the transformations into intermediate vacancy-ordered t-phases take place which in some studies are regarded as periodic approximants of 1D quasicrystals [11]. In the literature there are no data supporting the displacement-type transformation; however, there are indirect experimental evidences to suggest a possible instability of the crystal lattice in the quenched Al x Cu y Fe z b-phase.…”

Section: Introductionsupporting

confidence: 92%

Structural State of ?-Solid Solution in Quenched Quasicrystal-Forming Alloys of Al61Cu26Fe13

Шалаева

Prekul

2000

phys. stat. sol. (a)

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Electron microscopic investigations of the structural state have been carried out for the b(CsCltype)-phase in the quenched quasicrystal-forming two-phase (i + b) alloy Al 61 Cu 26 Fe 13 . We conclude that in the vicinity of compositions at which the icosahedral phase (i) is formed, at deviations from the composition Al 3 (Cu,Fe) 2 towards Al(Cu,Fe), the b(CsCl-type)-solid solution has a heterogeneous structure (a state similar to the diffuse incommensurable w-phase in b.c.c.-solid solutions). This structure includes the b-matrix with fine regions of correlated w-like displacements which in a certain way are interrelated with the t 3 -short-range order of substitution. It is concluded that the b(CsCl-type)-phase of Al 61± ±x Cu 26+y Fe 13± ±z reveals structural signs typical for electron-stabilized solid solutions, and because of this, the b-phase demonstrates a ªdielectricº behavior of its electronic properties. An assumption has been made that the regions with w-displacements are involved in the structural transformation b-phase 3 i-phase.

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Section: Introductionsupporting

confidence: 92%

Structural State of ?-Solid Solution in Quenched Quasicrystal-Forming Alloys of Al61Cu26Fe13

Шалаева

Prekul

2000

phys. stat. sol. (a)

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“…In contrast to d-Al--Co, the formation by melt quenching of d-Al--Ni is quite difficult and only possible around 75% Al (Tsuda, Nishida, Saitoh, Tanaka, Tsai, Inoue, Masumoto, 1996;Grushko, Holland-Moritz, 1997). Vacancy-ordered Al--Ni-Cu t-phases based on the CsCl-type, related to QC, are described by Chattopadhyay, Lele, Thangaraj, Ranganathan (1987).…”

Section: Discoverymentioning

confidence: 99%

Twenty years of structure research on quasicrystals. Part I. Pentagonal, octagonal, decagonal and dodecagonal quasicrystals

Steurer¹

2004

Zeitschrift Für Kristallographie - Crystalline Materials

244

102

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Is quasicrystal structure analysis a never-ending story? Why is still not a single quasicrystal structure known with the same precision and reliability as structures of regular periodic crystals? What is the state-of-the-art of structure analysis of axial quasicrystals? The present comprehensive review summarizes the results of almost twenty years of structure analysis of axial quasicrystals and tries to answer these questions as far as possible. More than 2000 references have been screened for the most reliable structural models of pentagonal, octagonal, decagonal and dodecagonal quasicrystals. These models, mainly based on diffraction data and/or on bulk and surface microscopic images are critically discussed together with the limits and potentialities of the respective methods employed.

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“…The vacancy ordered phases (VOPs) being an interesting class of intermetallic phases comes under the broad category of structures with ordered defects [2]. It has been shown that the vacancy ordered phase can be considered as an approximant phase to one-dimensional as well as two-dimensional decagonal quasicrystals [3][4][5]. VOPs represent a class of structure where compositions and diffraction effects display a close relationship with the golden mean,  (where, τ=1/2(5 +1).…”

Section: Introductionmentioning

confidence: 99%

Stability of mechanically alloyed vacancy ordered phase in Al₇₀Cu₁₅Ni₁₅alloy during annealing

Yadav¹,

Mukhopadhyay²,

Tiwari³

et al. 2010

J. Phys.: Conf. Ser.

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Abstract.A nano  3 vacancy-ordered phase in the Al-Cu-Ni alloy system has been synthesized with a composition close to Al 70 Cu 15 Ni 15 by mechanical alloying a mixture of elemental powder in a high-energy ball mill by varying milling time from 10 to 100 hours. The stability of nano-crystalline  3 vacancy-ordered phase has been studied under thermal annealing in vacuum as well as in air. The x-ray diffraction and transmission electron microscopy techniques were employed for characterization of the milled and annealed samples. The powder after 100 h of milling was found to contain mostly nano  3 phase with the partial ordering, and with crystallite sizes in the range of 10-20 nm along with a lattice strain of ~0.67 %. The milled powder, after annealing in vacuum at 700 ºC for 60 h, revealed the formation of a strain-free and ordered  3 phase with a crystallite size of 80 nm, indicating grain coarsening. It is interesting to note that the milled powder annealed in air at 700 ºC for 60 h showed the formation of (Cu,Ni)Al 2 O 4 type spinel phase with the lattice parameter of 8.1 Å and the lattice strain as 0.52 %. The average grain size of spinel phase was found to be ~ 40 nm.

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Vacancy ordered phases and one-dimensional quasiperiodicity

Cited by 90 publications

References 16 publications

Structural State of ?-Solid Solution in Quenched Quasicrystal-Forming Alloys of Al61Cu26Fe13

Structural State of ?-Solid Solution in Quenched Quasicrystal-Forming Alloys of Al61Cu26Fe13

Twenty years of structure research on quasicrystals. Part I. Pentagonal, octagonal, decagonal and dodecagonal quasicrystals

Stability of mechanically alloyed vacancy ordered phase in Al₇₀Cu₁₅Ni₁₅alloy during annealing

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Vacancy ordered phases and one-dimensional quasiperiodicity

Cited by 90 publications

References 16 publications

Structural State of ?-Solid Solution in Quenched Quasicrystal-Forming Alloys of Al61Cu26Fe13

Structural State of ?-Solid Solution in Quenched Quasicrystal-Forming Alloys of Al61Cu26Fe13

Twenty years of structure research on quasicrystals. Part I. Pentagonal, octagonal, decagonal and dodecagonal quasicrystals

Stability of mechanically alloyed vacancy ordered phase in Al70Cu15Ni15alloy during annealing

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Stability of mechanically alloyed vacancy ordered phase in Al₇₀Cu₁₅Ni₁₅alloy during annealing