X-ray and electron metallographic study of quasicrystalline AlMnSi Alloys

Robertson, J. L.; Misenheimer, M.E.; Moss, S. C.; Bendersky, Leonid A.

doi:10.1016/0001-6160(86)90163-x

Cited by 46 publications

(12 citation statements)

References 29 publications

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“…1 (c) according to the scheme of Cahn et al 14 The peaks in Fig. 1(c) are broader than those usually measured on melt-quenched samples, 19,20 indicating a smaller grain size for the sputtered film and a higher defect or phason strain 21,22 density. From a Gaussian fit to the Al(lll) reflection, we estimate an Al particle size of L -278 A.…”

Section: S(q)=[l M (Q)/n]-(f 2 (Q))]/(f(q))\mentioning

confidence: 89%

“…21 ' 22 In melt-quenched samples, for example, 30-jum particles may show correlations ranges of only 300-500 A. 19,20 Because this type of defect is inevitably associated with the growth of a quasicrystal, if we wish to treat Fig. 1 (a) as a defective quasicrystal pattern we must introduce additional phason strain into Fig.…”

Section: S(q)=[l M (Q)/n]-(f 2 (Q))]/(f(q))\mentioning

confidence: 99%

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Comparison of Amorphous and Quasicrystalline Films of SputteredAl0.72Mn0.22
Robertson
¹
,
Moss
²
,
Kreider
³

1988
Phys. Rev. Lett.
50
3
5
0
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X-ray data were collected on films of Alo.72Mno.22Sio.06 sputtered on NaCl at 45, 150, and 230 °C. The 45°C films show a typical metallic-glass structure factor, 5(g), while at 230°C the structure is quasicrystalline plus Al. A combined particle-size and phason strain broadening was applied to the normalized and reduced S(Q) for the 230°C film to bring it essentially into coincidence with the amorphous (45 °C) S(Q) leading us to conclude that the glass, or amorphous, phase represents a defect limit of the quasicrystal. PACS numbers: 61.50.Em, 61.40.+b, 61.55.Hg Conventional microcrystalline models have for some time been considered unsuccessful descriptions of the glassy state of simple metals and alloys. l The discovery of the icosahedral quasicrystal, 2 however, has revived interest in the structure of metallic glasses. As discussed by Widom 3 in his review of icosahedral phases, there is an intimate connection between the local order in glasses, icosahedral quasicrystals, and the crystalline Frank-Kasper phases. 4 The competition among them may be understood if we consider the ways in which frustration, induced by an attempt to close-pack tetrahedra, is relieved or realized. Frank 5 was the first to point out that liquids can naturally accommodate this frustration by forming icosahedral clusters that are clearly not little pieces of, say, an fee crystal. Sachdev and Nelson 6 have more recently developed the statistical mechanics of icosahedral order in dense liquids just above the glass transition and have calculated a structure factor, S(Q), which agrees rather well with the data on amorphous Fe. 7 For U-Pd-Si alloys, Kofalt et a/. 8 have shown with x-ray scattering a similarity in the pair correlation functions, G(r), for a quenched glass and a quasicrystal. Mayer et al 9 have also done an electron-diffraction study to determine the G(r) for an amorphous alloy of Alo.84Vo.i6, produced by electron irradiation of the quasicrystalline phase of the same alloy. In this work they demonstrate the similarity in structure between the "amorphized" quasicrystal and a conventional metallic glass. Urban Moser, and Kronmiiller 10 had previously obtained a very fine grain size for the quasicrystalline phase by annealing the amorphous phase produced by irradiation and had termed the microstructure "microquasicrystalline." Bendersky and Ridder, 11 however, produced increasingly fine droplets-and hence cooling rates-from atomized Alo.86Mn 014 alloys whose apparently amorphous structures, formed smoothly in the limit of high cooling rate, were not considered to be truly amorphous, as in a metallic glass, but rather "microquasicrystalline." Urban et al. n have reviewed this situation-glass versus microquasicrystal-and suggest that (a) the term "microquasicrystalline" may profitably be used only for the quasicrystal whose fine grain size, due to copious nucleation, cannot easily grow, and that (b) the competing amorphous phase, produced by irradiation, is indistinguishable from a conventional metallic glass. This resolution, ...

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Section: S(q)=[l M (Q)/n]-(f 2 (Q))]/(f(q))\mentioning

confidence: 89%

Section: S(q)=[l M (Q)/n]-(f 2 (Q))]/(f(q))\mentioning

confidence: 99%

Comparison of Amorphous and Quasicrystalline Films of SputteredAl0.72Mn0.22
Robertson
¹
,
Moss
²
,
Kreider
³

1988
Phys. Rev. Lett.
50
3
5
0
View full text Add to dashboard Cite

show abstract

“…Visible but distorted pentagon dodecahedra around w0.01 mm were observed in melt-quenched AlMnSi [79,80]. Visible but distorted pentagon dodecahedra around w0.01 mm were observed in melt-quenched AlMnSi [79,80].…”

Section: Stellated Polyhedronmentioning

confidence: 96%

Crystal Growth of Quasicrystals

Tsai

Cui

2015

Handbook of Crystal Growth

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“…Subsequently, Urban et al (1986) suggested that the contrast arose from internal strains in regions some 10 nm in size, which cause local lattice misorientations. Robertson et al (1986) also observed mottling in i-(AIMn), but on a 2-5 nm scale, and suggested that a connection might naturally exist between this mottling and the peak broadening observed in X-ray powder diffraction patterns (cf. Bancel et al, 1985).…”

Section: Introductionmentioning

confidence: 92%

“…Several authors have commented on the 'cloudy' or 'speckly' contrast characteristic of dark field images of icosahedral quasicrystals (Shechtman & Blech, 1985;Field & Fraser, 1984-85;Urban et al, 1985Urban et al, , 1986Knowles & Stobbs, 1986;Saito et al, 1986;Robertson et al, 1986), and the origins of this contrast have yet to be established unequivocally. Field & Fraser attributed the speckly contrast they obtained in weak beam micrographs of i-(AlMn) to fine crystallites which they estimated to be about 5 nm in size.…”

Section: Introductionmentioning

confidence: 99%

The inhomogeneity of the icosahedral phase in Al‐Mn and Al‐V

Knowles

Stobbs

1987

Journal of Microscopy

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SUMMARY The inherent differences between the various current structural models for the determination of the scattering behaviour of icosahedral materials are reviewed with the conclusion that the nature of their apparently characteristic inhomogeneity needs further clarification. Here it is shown that the dark field reflection and deviation parameter dependence of transmission electron microscope (TEM) contrast variations can be used to provide useful qualitative evidence for the nature of quasicrystal inhomogeneities. Results obtained using the technique are discussed for the icosahedral phases i‐(AlMn) and i‐(AlV).

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X-ray and electron metallographic study of quasicrystalline AlMnSi Alloys

Cited by 46 publications

References 29 publications

Comparison of Amorphous and Quasicrystalline Films of SputteredAl0.72Mn0.22
Robertson
¹
,
Moss
²
,
Kreider
³

1988
Phys. Rev. Lett.
50
3
5
0
View full text Add to dashboard Cite

Comparison of Amorphous and Quasicrystalline Films of SputteredAl0.72Mn0.22
Robertson
¹
,
Moss
²
,
Kreider
³

1988
Phys. Rev. Lett.
50
3
5
0
View full text Add to dashboard Cite

Crystal Growth of Quasicrystals

The inhomogeneity of the icosahedral phase in Al‐Mn and Al‐V

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X-ray and electron metallographic study of quasicrystalline AlMnSi Alloys

Cited by 46 publications

References 29 publications

Comparison of Amorphous and Quasicrystalline Films of SputteredAl0.72Mn0.22Robertson1, Moss2, Kreider3 1988Phys. Rev. Lett.50350View full textAdd to dashboardCite

Comparison of Amorphous and Quasicrystalline Films of SputteredAl0.72Mn0.22Robertson1, Moss2, Kreider3 1988Phys. Rev. Lett.50350View full textAdd to dashboardCite

Crystal Growth of Quasicrystals

The inhomogeneity of the icosahedral phase in Al‐Mn and Al‐V

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Comparison of Amorphous and Quasicrystalline Films of SputteredAl0.72Mn0.22
Robertson
¹
,
Moss
²
,
Kreider
³

1988
Phys. Rev. Lett.
50
3
5
0
View full text Add to dashboard Cite

Comparison of Amorphous and Quasicrystalline Films of SputteredAl0.72Mn0.22
Robertson
¹
,
Moss
²
,
Kreider
³

1988
Phys. Rev. Lett.
50
3
5
0
View full text Add to dashboard Cite