Continues Decomposition of Icosahedral Quasicrystals in AlCuFe Alloys

Liu, W.; Köster, Uwe; Załuska, A.

doi:10.1002/pssa.2211260134

Cited by 18 publications

(5 citation statements)

References 7 publications

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“…In [3] it was reported that it occurs during a reversible transformation from a rhombohedral approximant crystal to a quasicrystal Al63.5Cu12.5Fe24. In the same way, Liu et al [4] could observe a modulation in the course of a continuous decomposition of an Al-Cu-Fe IQC. The modulation state does then seem to be associated with an out of equilibrium situation which matches well the case here considering the very short time of localized loading during the scratch test.…”

Section: Resultsmentioning

confidence: 64%

Scratch-induced surface microstructures on the deformed surface of Al-Cu-Fe icosahedral quasicrystals

Brien

Brunet

et al. 2000

Materials Science and Engineering: A

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Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations of sintered Al-Cu-Fe icosahedral quasicrystal (IQC) have been carried out to understand the origin of some ductility previously noticed within tracks produced by standard tribological scratch tests. Transformation of the icosahedral phase to a modulated structure is shown and a transformation of the IQC to a bcc phase has been found beneath the tracks. Twins and dislocations have also been observed.

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Section: Resultsmentioning

confidence: 64%

Scratch-induced surface microstructures on the deformed surface of Al-Cu-Fe icosahedral quasicrystals

Brien

Brunet

et al. 2000

Materials Science and Engineering: A

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“…Local formation of rhombohedral micrograins or microdomains in the icosahedral structure is likely because there is a group-subgroup relation between the icosahedral and the rhombohedral structures. Rhombohedral microdomains in icosahedral crystal have also been observed in the Al-Cu-Fe system [14]. Two different types of rhombohedral approximants have been reported in Al-Cu-Fe alloys: a 2/1 approximant with a = 37.7 Å and α = 63.43 • ; a 3/2 approximant with a = 61.0 Å and α = 63.43 • .…”

Section: Inhomogeneous Structural Order In I-phase and The Approximantmentioning

confidence: 83%

“…By using the reported value of a R = 5.2 Å for the MgZnY icosahedral quasicrystal [16], the lattice constant of the 1/1 rhombohedral approximant is expected to have a = 2(1 + τ )a R = 27.2 Å. When compared with the pseudotwofold diffraction patterns of the 2/1 and 3/2 rhombohedral approximants reported by Liu et al [14], the approximant phase in the Mg-Zn-Y system can be identified as the 1/1 rhombohedral approximant [9].…”

Section: Inhomogeneous Structural Order In I-phase and The Approximantmentioning

confidence: 90%

“…The gradual change in structural order or the presence of intermediate structure between rhombohedral and icosahedral structures can be explained by the formation of microdomain structure with specific orientation of rhombohedra as in the Al-Cu-Fe system [14]. The formation of microdomains may be related to the compositional change in the I-phase.…”

Section: Inhomogeneous Structural Order In I-phase and The Approximantmentioning

confidence: 99%

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Microstructural evolution and the role of interfaces in Mg–Zn–Y alloys with high strength and formability

Chang

Lee

Kim

2008

J. Phys.: Condens. Matter

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Composites consisting of a quasicrystalline, icosahedral phase (I-phase) and ductile α-Mg can be fabricated by controlling the alloy composition in the Mg–Zn–Y alloy system. The I-phase in Mg–Zn–Y alloys shows a variation in structural order from a well-ordered icosahedral phase to a 1/1 rhombohedral approximant phase. The structural change in the icosahedral phase can be explained by microdomain formation due to compositional change during solidification. The characteristic of strong bonding between icosahedral particles and the α-Mg matrix indicates that the structural change from I-phase to crystalline phase is not discontinuous, but gradual. The interface layer of α-Mg with several nm thickness preserves an orientational relationship with the I-phase, although the remaining α-Mg shows a different orientation due to plastic deformation during deformation (rolling process). Such a strong interface can provide an excellent combination of high strength and formability in Mg-based alloys, enabling application as lightweight structural parts.

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“…i-Al±Cu±Fe(Si). Several transitions of the i phase have been observed depending on sample composition and annealing conditions: QC to cubic h1, 1i (Quivy et al, 1996) and rhombohedral h2, 1i , h3, 2i (Liu et al, 1991) or h5, 3i approximants (Liu & Ko È ster, 1993). In some cases, an intermediate linear-phason strained quasicrystalline phase or a transient modulated i phase with satellite re¯ections along the ®vefold directions was observed .…”

Section: Quasicrystalline To Crystallinementioning

confidence: 99%

Structural phase transitions from and to the quasicrystalline state

Steurer

2004

Acta Cryst Sect A

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Phase transitions from and to the quasicrystalline state show a typical signature due to some structural peculiarities. Both quasicrystals and most of their translationally periodic transformation products, the approximants, consist of the same basic structural units ('clusters'). This is the cause of low-energy interfaces between the newly forming phase and the parent phase. It is also the origin of the rather high stability of the frequently resulting orientationally twinned nanodomain structures. Owing to topological incompatibilities between quasiperiodic and periodic structures, purely displacive phase transitions are impossible. Diffusion of a significant fraction of atoms, at least on the scale of the cluster diameters, always has to take place. Locally similar icosahedral structural ordering between parent phase and nucleating phase is also responsible for the frequently occurring formation of icosahedral quasicrystals from undercooled liquid alloys or during devitrification of metallic glasses. The different types of experimentally observed phase transitions are discussed, from amorphous to quasicrystalline, quasicrystalline to ordered/disordered quasicrystalline and quasicrystalline to crystalline as a function of temperature, pressure, irradiation and high-energy ball milling, respectively.

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Continues Decomposition of Icosahedral Quasicrystals in AlCuFe Alloys

Cited by 18 publications

References 7 publications

Scratch-induced surface microstructures on the deformed surface of Al-Cu-Fe icosahedral quasicrystals

Scratch-induced surface microstructures on the deformed surface of Al-Cu-Fe icosahedral quasicrystals

Microstructural evolution and the role of interfaces in Mg–Zn–Y alloys with high strength and formability

Structural phase transitions from and to the quasicrystalline state

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