Topological and Chemical Short-Range Order in Undercooled and Stable Melts of Al13(Co,Fe)4 Alloys

ABSTRACTThe short-range order of stable and deeply undercooled liquids of Al13(Co,Fe)4 alloys forming polytetrahedral phases is investigated by combining the containerless processing technique of electromagnetic levitation with elastic neutron scattering. Partial structure factors were inferred from the diffraction data which allow an analysis of both, the topological and the chemical short-range order of these alloy melts as a function of the temperature.

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Neutron Scattering Experiments on the Short-Range Order in Undercooled Metallic Melts

MRS Proceedings ◽

10.1557/proc-754-cc7.2 ◽

2002 ◽

Vol 754 ◽

Author(s):

Dirk Holland-Moritz ◽

Thomas Schenk ◽

Virginie Simonet ◽

Robert Bellissent ◽

Pierre Convert ◽

...

Keyword(s):

Neutron Scattering ◽

Short Range ◽

Short Range Order ◽

Electromagnetic Levitation ◽

Range Order ◽

Icosahedral Symmetry ◽

Elastic Neutron ◽

Structure Factors ◽

Metallic Melts ◽

Undercooled Melts

ABSTRACTThis work presents investigations on the short-range order of stable and deeply undercooled melts of the pure elements Fe, Zr and Ni. The liquids were undercooled by use of the electromagnetic levitation technique, which was combined with elastic neutron scattering in order to determine the structure factors of the liquids as a function of the temperature. The diffraction experiments provide evidence that a short-range order based on aggregates of icosahedral symmetry prevails in the melt. This short-range order is observed even at temperatures above the melting temperature and gets more pronounced if the liquids are undercooled.

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Diskussion der diffusen Laue-Streuung flüssiger Legierungen / Remarks on the Diffuse Laue-Scattering of Liquid Alloys

Zeitschrift für Naturforschung A ◽

10.1515/zna-1972-0623 ◽

1972 ◽

Vol 27 (6) ◽

pp. 1018-1019

Author(s):

H. Ruppersberg ◽

K. Goebbels

Keyword(s):

Short Range ◽

Short Range Order ◽

Range Order ◽

Liquid Alloys ◽

Partial Structure ◽

Structure Factors

AbstractPrepeaks in the partial structure factors of liquid alloys are interpreted as a modulation in the diffuse Laue-scattering, caused by chemical short range order. It is shown and experimentally confirmed that the partial structure factors can become lower than -1. It is unlikely that a modulation appears in only one of the three partials; rather a chemical short range order should be indicated in all three partial structure factors.

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Partial structure factors and chemical short-range order in Ni33Y67and Cu33Y67metallic glasses

Journal of Physics F Metal Physics ◽

10.1088/0305-4608/17/2/004 ◽

1987 ◽

Vol 17 (2) ◽

pp. 315-333 ◽

Cited By ~ 42

Author(s):

M Maret ◽

P Chieux ◽

P Hicter ◽

M Atzmon ◽

W L Johnson

Keyword(s):

Short Range ◽

Short Range Order ◽

Range Order ◽

Partial Structure ◽

Structure Factors

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Partial Atomic Distribution Functions of Liquid Fe75B25

Zeitschrift für Naturforschung A ◽

10.1515/zna-1988-0214 ◽

1988 ◽

Vol 43 (2) ◽

pp. 177-180 ◽

Cited By ~ 1

Author(s):

N. Mattern ◽

W. Matz ◽

H. Hermann

Keyword(s):

Neutron Diffraction ◽

Short Range ◽

Short Range Order ◽

Distribution Functions ◽

Range Order ◽

Experimental Results ◽

Partial Structure ◽

X Ray ◽

Atomic Distribution ◽

Structure Factors

Abstract Partial structure factors and atomic distribution functions for liquid Fe75 B25 were determined for the Fe-Fe and Fe-B pairs by means of X-ray and neutron diffraction. The experimental results show a strong chemical short-range order in the melt which is similar to that of amorphous Fe75B25.

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Short Range Structure of Amorphous Ni50Ta50-Alloys by Means of X-Ray- and Neutron-Diffraction

Zeitschrift für Naturforschung A ◽

10.1515/zna-1992-7-806 ◽

1992 ◽

Vol 47 (7-8) ◽

pp. 826-832 ◽

Cited By ~ 1

Author(s):

H. Uhlig ◽

L. Rohr ◽

H.-J. Güntherodt ◽

P. Fischer ◽

P. Lamparter ◽

...

Keyword(s):

Neutron Diffraction ◽

Short Range ◽

Short Range Order ◽

Nearest Neighbor ◽

Range Order ◽

Partial Structure ◽

X Ray ◽

Coordination Numbers ◽

Binding Behavior ◽

Structure Factors

Abstract Amorphous Ni50Ta50-samples with their high crystallization temperature of 985 K were investigated. To evaluate the three partial structure factors of amorphous Ni50Ta50 one X-ray diffraction experiment was performed with Ni50Ta50 and two neutron diffraction experiments with Co10Ni40Ta50 and with Ni50Ta50, respectively. The Bhatia-Thornton partial structure factor SCC(Q) indicates rather strong chemical short range order which also explains the premaximum observed in the Faber-Ziman partial SNiNi(Q)-function. The nearest neighbor distance is 2.82 Å for Ni-Ni, 2.91 Å for Ta-Ta, and is shortest for Ni-Ta, 2.44 Å. The coordination numbers are NNiNi = 4.9, NTaTa = 8.2, and NNiTa = 6.0. We report on the chemical short range order and the possible binding behavior in a-Ni50Ta50 and compare the present results with those reported in the literature on a-Ni40Ti60 as well as on a-Ni55Ta45

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Definition of partial structure factors and compositional short range order (CSRO)

Novel Application of Anomalous (Resonance) X-ray Scattering for Structural Characterization of Disordered Materials - Lecture Notes in Physics ◽

10.1007/bfb0025748 ◽

2005 ◽

pp. 10-19

Keyword(s):

Short Range ◽

Short Range Order ◽

Range Order ◽

Partial Structure ◽

Structure Factors ◽

Definition Of

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Undercooling And X-Ray Structural Studies Of Ti-Zr-Ni Liquids

MRS Proceedings ◽

10.1557/proc-754-cc10.5 ◽

2002 ◽

Vol 754 ◽

Author(s):

G.W. Lee ◽

A.K. Gangopadhyay ◽

K.F. Kelton ◽

R.W. Hyers ◽

T.J. Rathz ◽

...

Keyword(s):

Short Range ◽

Short Range Order ◽

Icosahedral Phase ◽

Range Order ◽

X Ray Diffraction ◽

Containerless Processing ◽

X Ray ◽

Ni Alloys ◽

Nucleation Barrier ◽

Maximum Undercooling

ABSTRACTMaximum undercooling results for the icosahedral phase (i-phase), polytetrahedral C14 Laves phase, and solid solution phases are presented as a function of composition in Ti-Zr-Ni liquids. Containerless processing was achieved using the electrostatic levitation facility located at NASA/Marshall Space Flight Center. The maximum reduced undercooling decreases with increasing icosahedral short-range order in the ordered phase. The first synchrotron x-ray diffraction data from aerodynamically levitated liquids of Ti-Zr-Ni alloys suggest an icosahedral short-range order in the liquids, supporting Frank's hypothesis, correlating icosahedral order in the liquid with the nucleation barrier to the crystal phase. The strong negative heats of mixing between Ti/Zr and Ni and their relative atomic sizes likely favor the formation of this local icosahedral order.

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Structural Investigation of the Metallic Glasses Mg85.5Cu14.5 and Mg70Zn30

Zeitschrift für Naturforschung A ◽

10.1515/zna-1983-0208 ◽

1983 ◽

Vol 38 (2) ◽

pp. 142-148 ◽

Cited By ~ 33

Author(s):

E. Nassif ◽

P. Lamparter ◽

W. Sperl ◽

S. Steeb

Keyword(s):

Short Range ◽

Short Range Order ◽

Pair Correlation ◽

Range Order ◽

Order Effects ◽

X Ray Diffraction ◽

X Ray ◽

Structure Factors ◽

Similar Chemical ◽

Total Structure

Abstract The total structure factors as well as the total pair correlation functions for amorphous Mg85.5Cu14.5 (by neutron and X-ray diffraction) and for amorphous Mg70Zn30 (by X-ray diffraction) were determined. Both alloys show similar chemical short range order effects. From the total pair correlation function of the Mg85.5Cu14.5 glass, partial coordination numbers and atomic distances could be extracted. Comparison with the structure of crystalline Mg2Cu suggests that the short range order around the copper atoms is similar in the amorphous and the crystalline phase. The densities of both amorphous alloys were measured yielding negative excess volumina.

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Neutron- and X-ray-Diffraction Study on the Structure of Amorphous Co25Ti75

Zeitschrift für Naturforschung A ◽

10.1515/zna-1987-0103 ◽

1987 ◽

Vol 42 (1) ◽

pp. 7-12 ◽

Cited By ~ 2

Author(s):

A. Müller ◽

E. Bühler ◽

P. Lamparter ◽

S. Steeb

Keyword(s):

Diffraction Study ◽

Short Range ◽

Short Range Order ◽

Range Order ◽

Diffraction Experiment ◽

X Ray Diffraction ◽

X Ray ◽

Coordination Numbers ◽

Structure Factors ◽

Melt Spin

Amorphous Co25Ti75 could be produced using the melt-spin-technique. A neutron- and a X-ray-diffraction experiment was performed. Assuming SNC ≡ 0 the partial Bhatia Thornton structure factors SNN and SCC as well as the partial coordination numbers were calculated. The discussion yields the atomic distances and the chemical short range order parameters.

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