Phase Decomposition in Cu-Ti Metallic Glass

1983 ◽  
Vol 28 ◽  
Author(s):  
R. D. Shull ◽  
S. P. Singhal ◽  
B. Mozer ◽  
A. Maeland
Keyword(s):  
Neutron Diffraction ◽  
Metallic Glass ◽  
Melt Spinning ◽  
Large Angle ◽  
Amorphous State ◽  
Glass Ribbon ◽  
Amorphous Structure ◽  
Phase Decomposition ◽  
X Ray ◽  
Diffraction Patterns

ABSTRACTA metallic glass ribbon of Cu55Ti45 prepared by melt spinning was examined by x-ray, neutron, and electron diffraction, by small angle neutron diffraction (SANS), transmission electron microscopy (TEM), and by differential thermal analysis (DTA). In the liquid quenched condition large angle diffraction data (both x-ray and neutron) show the broad banded structure typical of the amorphous state. The SANS data, however, exhibit highly anisotropic patterns arising from the phase decomposition during solidification. Ribbons annealed below the glass transition temperature (Tg ) produced neutron diffraction patterns of materials with the same amorphous structure combined with a new short range order; and the SANS patterns retained the asymmetry of the as-quenched material. Ribbons annealed above the crystallization temperature (Tc) show both isotropic and anisotropic contributions to the SANS patterns. Formation of the equilibrium TiCu phase occurs directly from the metallic glass at Tc. The equilibrium Ti3Cu4 phase, however, forms from the TiCu phase at slightly higher temperatures.

Crystal structure of magnesium dichloride decahydrate determined by X-ray and neutron diffraction under high pressure

2015 ◽  
Vol 71 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Kazuki Komatsu ◽  
Ayako Shinozaki ◽  
Shinichi Machida ◽  
Takuto Matsubayashi ◽  
Mao Watanabe ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Neutron Diffraction ◽  
Amorphous State ◽  
Water Molecules ◽  
X Ray ◽  
The Difference ◽  
Diffraction Patterns ◽  
Difference Fourier ◽  
First Time

Magnesium dichloride decahydrate (MgCl2·10H2O) and its deuterated counterpart (MgCl2·10D2O) are identified for the first time byin-situpowder synchrotron X-ray and spallation neutron diffraction. These substances are crystallized from a previously unidentified nanocrystalline compound, which originates from an amorphous state at low temperature. A combination of a recently developed autoindexing procedure and the charge-flipping method reveals that the crystal structure of MgCl2·10H2O consists of an ABCABC... sequence of Mg(H2O)6octahedra. The Cl−anions and remaining water molecules unconnected to the Mg2+cations bind the octahedra, similar to other water-rich magnesium dichloride hydrates. The D positions in MgCl2·10D2O, determined by the difference Fourier methods using the neutron powder diffraction patterns at 2.5 GPa, show the features such as bifurcated hydrogen bonds and tetrahedrally coordinated O atoms, which were not found in other forms of magnesium chloride hydrates.

scholarly journals X-Ray and Neutron Diffraction of Amorphous Nickel-Zirconium-Alloys as Prepared in Different Ways

1991 ◽  
Vol 46 (6) ◽  
pp. 491-498 ◽  
Author(s):  
L. Schultz ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Neutron Diffraction ◽  
Short Range ◽  
Melt Spinning ◽  
Short Range Order ◽  
Pair Correlation ◽  
Zirconium Alloys ◽  
X Ray ◽  
Coordination Numbers ◽  
Structure Factors ◽  
The One

AbstractThe structure of amorphous NiχZr100-χ-alloys (Χ= 30, 31, 34, 63.7, and 65), which were produced by melt spinning (MS), mechanical alloying (MA), and sputtering (SP) was studied by X-ray- and neutron diffraction yielding structure factors, pair correlation functions, coordination numbers, atomic distances, and Warren-Cowley chemical short range order parameters. The atomic arrangement within the first coordination sphere is independent of the method of preparation while in the second and higher spheres it differs between the MS- and the MA-alloys on the one side and the SP-specimens on the other side. Thus one understands that some physical properties of the different specimens differ

scholarly journals Neutron and X-ray powder diffraction study of skutterudite thermoelectrics

2016 ◽  
Vol 31 (1) ◽  
pp. 16-22
Author(s):  
H. Wang ◽  
M. J. Kirkham ◽  
T. R. Watkins ◽  
E. A. Payzant ◽  
J. R. Salvador ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Melt Spinning ◽  
Lattice Parameter ◽  
Type Material ◽  
General Motors ◽  
X Ray Diffraction ◽  
Filling Fraction ◽  
Cubic Symmetry ◽  
X Ray ◽  
P Type

N- and p-type filled-skutterudite materials prepared for thermoelectric power generation modules were analyzed by neutron diffraction at the POWGEN beam line of the Spallation Neutron Source (SNS) and X-ray diffraction (XRD). The skutterudite powders were processed by melt spinning, followed by ball milling and annealing. The n-type material consists of Ba–Yb–Co–Sb and the p-type material consists of Di–Fe–Ni–Sb or Di–Fe–Co–Sb (Di = didymium, an alloy of Pr and Nd). Powders for prototype module fabrication from General Motors and Marlow Industries were analyzed in this study. XRD and neutron diffraction studies confirm that both the n- and p-type materials have cubic symmetry. Structural Rietveld refinements determined the lattice parameters and atomic parameters of the framework and filler atoms. The cage filling fraction was found to depend linearly on the lattice parameter, which in turn depends on the average framework atom size. This knowledge may allow the filling fraction of these skutterudite materials to be purposefully adjusted, thereby tuning the thermoelectric properties.

X-ray- and Neutron-diffraction Studies with Quasicrystalline and Amorphous Al-V- and Al-Mn-alloys

1990 ◽  
Vol 45 (5) ◽  
pp. 627-638
Author(s):  
S. Seehafer ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Neutron Diffraction ◽  
Coordination Number ◽  
Correlation Functions ◽  
Melt Spinning ◽  
Pair Correlation ◽  
Partial Density ◽  
Isomorphous Substitution ◽  
Hard Sphere Model ◽  
X Ray ◽  
Structure Factors

Abstract Amorphous and quasicrystalline samples of Al84Mn16 and Al84V16 were produced by sputtering and melt-spinning, respectively. From X-ray and neutron-diffraction-results the total structure factors were evaluated. For amorphous as well as for quasicrystalline Al84V16 the partial SAl-Al- and SAl-V-structure factors were obtained, which yield the corresponding partial pair correlation functions, the atomic distances, and the partial coordination numbers. Also some information concerning the partial Bhatia-Thornton correlation functions could be obtained. Both the amorphous and the quasicrystalline Al-V-alloys show a linear expansion by a factor of 1.03 compared to the corresponding Al-Mn-alloy. The two amorphous alloys can be designed as isomorphous, whereas the quasicrystalline ones show pronounced deviations in the distance between unequal atoms. The shortest atomic distance in amorphous Al84V16 is 2.69 A, being,formed by Al-V-pairs with a coordination number 2. The nearest Al-Al-distance amounts to 2.84 A with a coordination number 8. The partial density-concentration correlation function clearly deviates from the hard sphere model. With the quasicrystalline specimens, the isomorphous substitution of Mn- and V-atoms is not perfect. The Al-V-correlation is split up, and this is not observed for the Al-Mn-correlation. Comparison of the amorphous and the corresponding quasicrystalline alloy shows some similarities

Nanocrystallization of Cobalt Based Metallic Glass

2009 ◽  
Vol 67 ◽  
pp. 25-32 ◽  
Author(s):  
A.P. Srivastava ◽  
Dinesh Srivastava ◽  
K.G. Suresh ◽  
G.K. Dey
Keyword(s):  
Metallic Glass ◽  
Melt Spinning ◽  
Amorphous Ribbon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Addition ◽  
Isothermal Analysis ◽  
Effect Of Copper ◽  
Melt Spinning Technique

Effect of copper addition in a Metallic glass 2714A on the nanocrystallization characteristics have been examined in this study. Amorphous ribbon of the alloy composition Co64.5 Fe3.5 Si16.5 B13.5 Ni1Cu1 were prepared by melt spinning technique. Nanocrystallization kinetics was studied using differential scanning calorimeter technique. The kinetic parameters such as activation energy and Avrami exponent were determined using two different non-isothermal analysis methods. The kinetic behavior of individual crystallization event has been rationalized on the basis of these results. The role of addition of copper on the crystallization behavior has been understood by comparing with Metallic glass 2714A. The isothermally annealed nanocrystallized microstructures were characterized by X-ray diffraction.

scholarly journals Effect of Fe-Ni Substitution in FeNiSiB Soft Magnetic Alloys Produced by Melt Spinning

2021 ◽  
Vol 21 (4) ◽  
pp. 79-89
Author(s):  
Muhammed Fatih Kılıçaslan ◽  
Yasin Yılmaz ◽  
Bekir Akgül ◽  
Hakan Karataş ◽  
Can Doğan Vurdu
Keyword(s):  
Melt Spinning ◽  
Amorphous Structure ◽  
Soft Magnetic Materials ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
Sem Images ◽  
X Ray ◽  
Soft Magnetic Alloys ◽  
Fe Content ◽  
Rapid Solidification Technique

Abstract Alloys of FeNiSiB soft magnetic materials containing variable Fe and Ni contents (wt.%) have been produced by melt spinning method, a kind of rapid solidification technique. The magnetic and structural properties of FeNiSiB alloys with soft magnetic properties were investigated by increasing the Fe ratio. X-ray diffraction analysis and SEM images shows that the produced alloy ribbons generally have an amorphous structure, together with also partially nanocrystalline regions. It was observed that the structure became much more amorphous together with increasing Fe content in the composition. Among the alloy ribbons, the highest saturation magnetization was obtained as 0.6 emu/g in the specimen with 50 wt.% Fe. In addition, the highest Curie temperature was observed in the sample containing 46 wt.% Fe.

scholarly journals A Multiple Twin-Roller Casting Technique for Producing Metallic Glass and Metallic Glass Composite Strips

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3842
Author(s):  
Wu ◽  
Zhang ◽  
Chen ◽  
Li ◽  
Zhang
Keyword(s):  
Metallic Glass ◽  
Melt Spinning ◽  
Amorphous State ◽  
Glass Composite ◽  
Solidification Temperature ◽  
Casting Technique ◽  
Glass Composites ◽  
Mold Casting ◽  
Temperature Ranges ◽  
The Common

To date it has not been possible to produce metallic glass strips with a thickness larger than 150 m via single-roller melt spinning technique, and it remains challenging to produce thick metallic glass strips. In this work, a multiple twin-roller casting technique is proposed for producing thick metallic glass and metallic glass composite strips. A triple twin-roller casting device, as a specific case of the multiple twin-roller, was designed and manufactured. The triple twin-roller device possesses a high cooling rate and involves a long contact time between the melt and the strip, which makes it an efficient technique for producing metallic glass strips that avoids crystallization, although the solidification temperature ranges of metallic glasses are as wide as several hundred Kelvins. The two prepared metallic glass (MG) strips are in a fully amorphous state, and the MG strip shows excellent capacity of stored elastic energy under 3-point bending. Furthermore, the Ti-based metallic glass composite strip produced via the triple twin-roller casting exhibits a novel microstructure with much finer and more homogenously orientated -Ti crystals, as compared with the microstructure of metallic glass composites produced by the common copper mold casting technique.

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