Investigation of the structure and properties of quartz in the α-β transition range by neutron diffraction and mechanical spectroscopy

The effect of partial crystallization on the mechanical properties of a Zr based bulk metallic glass (Vitreloy 1) is investigated. Viscoelastic properties are studied by mechanical spectroscopy in large frequency and temperature ranges, both below or above the glass transition temperature (Tg), whereas viscoplastic properties are investigated by compression tests . To study the interaction between crystallization and mechanical properties at high temperature, nanocomposites are produced thanks to appropriate heat treatments. Formation of nanocrystalline particles induces an increase of the storage elastic modulus, especially in the glass transition range, where this modulus is very low in the amorphous material. It also results in a decrease of the loss elastic modulus, corresponding to a decrease of the atomic mobility. Finally, partial crystallization induces very large hardening revealed by the compression tests but the hardening extent depends strongly on the applied strain rate.

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Mechanical Spectroscopy and Neutron Diffraction Studies in Fe-Al-Si Alloys

Solid State Phenomena - Interaction between Defects and Anelastic Phenomena in Solids ◽

10.4028/3-908451-53-1.91 ◽

2008 ◽

pp. 91-98

Author(s):

O.A. Lambri ◽

J.I. Pérez-Landazábal ◽

G.J. Cuello ◽

J.A. Cano ◽

V. Recarte ◽

...

Keyword(s):

Neutron Diffraction ◽

Mechanical Spectroscopy

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Magnetic Structure and Properties of the Intercalated Compound Fe0.5TiSe2

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.168-169.157 ◽

2010 ◽

Vol 168-169 ◽

pp. 157-160 ◽

Cited By ~ 1

Author(s):

N.V. Baranov ◽

N.V. Selezneva ◽

Valery G. Pleshchev ◽

N.V. Mushnikov ◽

V.I. Maksimov

Keyword(s):

Magnetic Field ◽

Crystal Structure ◽

Electrical Resistivity ◽

Neutron Diffraction ◽

Magnetic Moments ◽

Structure And Properties ◽

Monoclinic Crystal ◽

X Ray ◽

Monoclinic Crystal Structure ◽

A Value

The intercalated compound Fe0.5TiSe2 has been studied by means of X-ray, neutron diffraction, electrical resistivity and magnetization measurements. This compound with Fe atoms located between Se-Ti-Se sandwiches has a monoclinic crystal structure and exhibits a long-range antiferromagnetic (AF) ordering below TN = 135 K. At T < TN, the Fe magnetic moments with a value ~ 3.0 µB are directed at an angle of (74.4±0.5)º to the layers and form a tilted antiferromagnetic structure with the propagation vector (½, 0, ½). It has been shown that application of magnetic field above 300 kOe may lead to transformations of the AF structure.

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Mechanical Spectroscopy and Neutron Diffraction Studies in Fe-Al-Si Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.137.91 ◽

2008 ◽

Vol 137 ◽

pp. 91-98 ◽

Cited By ~ 3

Author(s):

O.A. Lambri ◽

José Ignacio Pérez-Landazábal ◽

G.J. Cuello ◽

J.A. Cano ◽

Vicente Recarte ◽

...

Keyword(s):

Thermal Treatment ◽

Neutron Diffraction ◽

Grain Boundary ◽

Grain Boundaries ◽

Relaxation Peak ◽

Magnetic Response ◽

Mechanical Spectroscopy ◽

Order Degree ◽

Boundary Relaxation ◽

Degree Of Order

Mechanical spectroscopy and neutron diffraction studies were performed on several samples with compositions Fe - 25 at. % (Al + Si) and Fe - 15 at. % (Al + Si). It was found that the solute grain boundary relaxation is strongly dependent on the degree of order in the sample. A decrease in the orderdegree allows the development of a relaxation peak at around 1000 K during cooling from 1200 K. In contrast, if the order degree is not decreased, the grain boundaries remain locked and consequently the relaxation peak does not appear. The magnetic response both in the asquenched and after thermal treatment states was also explored and correlated to the microstructural state.

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Change of Structure and Properties of 51CrV4 Shaft Caused by Thermo-Mechanical Treatment

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.137.169 ◽

2008 ◽

Vol 137 ◽

pp. 169-180 ◽

Cited By ~ 2

Author(s):

Jürgen Göken ◽

Manuel Maikranz-Valentin ◽

Kurt Steinhoff ◽

Tatiana S. Pavlova ◽

Tatiana V. Ivleva ◽

...

Keyword(s):

Mechanical Treatment ◽

Cold Work ◽

Cyclic Stress ◽

Special Treatment ◽

Structure And Properties ◽

Spectroscopy Technique ◽

Mechanical Spectroscopy ◽

Mechanical And Physical Properties ◽

Dislocation Behaviour ◽

Simultaneous Influence

The simultaneous influence of both thermal and mechanical treatment was applied to produce a geometrically complex shaft from 51CrV4 steel. This special treatment led to the formation of adjacent microstructures which were significantly different from each other. It was found that these microstructural changes were accompanied by a change of mechanical properties in terms of hardness, electrical resistivity and especially internal friction. Specimens for structural studies and study of mechanical and physical properties were taken out from different places of the produced shaft and tested in order to verify and understand the obtained gradation. The significant variations in properties could be explained in terms of structure and dislocation behaviour under applied cyclic stress using mechanical spectroscopy technique. The cold-work (Snoek-Köster) peak was recognised and analysed in the structure of this steel.

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The structure and properties of methane adsorbed on graphitized carbon black determined by neutron diffraction

Molecular Physics ◽

10.1080/00268978100101541 ◽

1981 ◽

Vol 43 (3) ◽

pp. 601-620 ◽

Cited By ~ 30

Author(s):

T. Rayment ◽

R.K. Thomas ◽

G. Bomchil ◽

J.W. White

Keyword(s):

Neutron Diffraction ◽

Carbon Black ◽

Graphitized Carbon Black ◽

Structure And Properties ◽

Graphitized Carbon

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Antisymmetric features of atomic charge density: Their significance in studies of electron redistribution accompanying bonding, and their relevance to thegeneral problem of structure and properties of molecules

Australian Journal of Chemistry ◽

10.1071/ch9650595 ◽

1965 ◽

Vol 18 (5) ◽

pp. 595 ◽

Cited By ~ 5

Author(s):

B Dawson

Keyword(s):

Neutron Diffraction ◽

Charge Density ◽

Elevated Temperatures ◽

Covalent Bond ◽

Atomic Charge ◽

Electronic Charge ◽

Structure And Properties ◽

Hydrogen Atoms ◽

X Ray ◽

Molecular Systems

A discussion is given of aspects of atomic charge density which possess the property of antisymmetry about the reference nuclear centre. It is shown that components of electronic charge density displaying this property must be an integral part of all bonded atoms possessing non-centric environments. The significance of such components for detailed X-ray diffraction studies of the electron redistribution which characterizes covalent bond formation is demonstrated for the case of carbon in diamond, and it is shown that the so-called "forbidden" 222 reflexion there is a natural consequence of antisymmetric features required by the non-centric (tetrahedral) disposition of bonded atoms in this lattice. Detailed X-ray studies of anthracene, salicylic acid, and cyanuric acid are cited to illustrate the importance and generality of antisymmetry concepts in accurate examinations of molecular systems; their significance in explaining long-standing discrepancies in the location of hydrogen atoms by X-ray and neutron diffraction methods is also noted. The discussion also demonstrates the relevance of antisymmetry to recent important neutron diffraction studies of fluorite structures at different elevated temperatures. Here, the accessible aspects of atomic charge density are those of nuclear charge density, i.e. nuclear vibrational behaviour, and it is shown that the presence of significant anharmonicity in the anionic vibrational pattern is responsible for the unusual diffraction effects observed. This anharmonicity has the same antisymmetry characteristics as those responsible for the 222 reflexion observed in X-ray studies of diamond. It is predicted that .future neutron studies of diamond structures (C, Si, Ge) at elevated temperatures should reveal a range of "forbidden" reflexions produced by antisymmetric components in the nuclear motions about their equilibrium positions. The discussion concludes with brief comments on the multipolar nature of bonded atoms arising from antisymmetric components in their electronic charge densities. Preliminary remarks are made on the relevance of the multipole concept to general problems of structure and properties of molecular systems.

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