Neutron diffraction study of the Ti1-xMoxC alloy

Abstract In this work, the crystal structure and (RMSD) root-mean-square displacement of atoms in new cubic refractory interstitial alloys Ti0.74Mo0.26C and Ti0.70Mo0.30C were determined by neutron diffraction. These alloys are obtained by powder metallurgy by sintering fine powders of cubic titanium carbides TiC and molybdenum MoC. The values of the RMSD of atoms in these alloys, obtained by the methods of least squares and full-profile analysis from the neutron diffraction data, turned out to be identical. They turned out to be much larger than in the stoichiometric TiC alloy, which has a similar cubic structure and close geometric parameters of atoms with the Ti0.74Mo0.26C and Ti0.70Mo0.30C alloys. These alloys were explained by the occurrence of large static distortions in the lattice of the Ti0.70Mo0.30C alloy due to the differences in the masses and atomic radii of the titanium and molybdenum elements.

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A neutron diffraction study of xylitol: derivation of mean square internal vibrations for H atoms from a rigid-body description

Acta Crystallographica Section B Structural Science ◽

10.1107/s010876810301557x ◽

2003 ◽

Vol 59 (5) ◽

pp. 653-663 ◽

Cited By ~ 21

Author(s):

Anders Østergaard Madsen ◽

Sax Mason ◽

Sine Larsen

Keyword(s):

Neutron Diffraction ◽

Rigid Body ◽

Diffraction Study ◽

Mean Square Displacement ◽

Neutron Diffraction Study ◽

Mean Square ◽

Anisotropic Displacement Parameters ◽

Good Agreement ◽

Internal Vibrations

A neutron diffraction study of xylitol (C5O5H12) is presented. The nuclear anisotropic displacement parameters have been analysed showing that the carbon–oxygen skeleton conforms to a rigid-body (TLS) description. Applying this TLS model to the xylitol H atoms allows characterization of the internal molecular displacements of the H nuclei, assuming that the observed H nuclear mean-square displacements are a sum of the internal displacements and rigid-body displacements. These internal molecular displacements are very similar for chemically equivalent H atoms and in good agreement with the values obtained by other methods. In all cases the smallest eigenvector of the residual mean-square displacement tensor is almost parallel to the X—H bond. The use of ab initio calculations to obtain the internal vibrations in xylitol is discouraging. Another 12 structures extracted from the literature which have been investigated by neutron diffraction were subjected to a similar analysis. The results for the nine compounds investigated at low temperature conform to the results from xylitol and provide estimates of the internal vibrations of H atoms in a range of chemical environments.

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MRIA - A Program for a Full Profile Analysis of Powder Neutron-Diffraction Time-of-Flight (Direct and Fourier) Spectra

Materials Science Forum ◽

10.4028/www.scientific.net/msf.79-82.283 ◽

1991 ◽

Vol 79-82 ◽

pp. 283-288

Author(s):

V.B. Zlokazov ◽

V.V. Chernyshev

Keyword(s):

Neutron Diffraction ◽

Profile Analysis ◽

Time Of Flight ◽

Powder Neutron Diffraction ◽

Full Profile ◽

Fourier Spectra

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A NEUTRON DIFFRACTION STUDY OF A SUPERCONDUCTING CUPRATE OF THE Bi–Ca–Sr–Cu–O SYSTEM CONTAINING TWO Cu-O SHEETS

International Journal of Modern Physics B ◽

10.1142/s0217979289000348 ◽

1989 ◽

Vol 03 (03) ◽

pp. 445-454 ◽

Cited By ~ 4

Author(s):

A. SEQUEIRA ◽

H. RAJAGOPAL ◽

L. GANAPATHI ◽

R. VIJAYARAGHAVAN ◽

C. N. R. RAO

Keyword(s):

Neutron Diffraction ◽

Diffraction Study ◽

Profile Analysis ◽

Neutron Diffraction Study ◽

Diffraction Profile ◽

Space Group

The structure of a nominally Ca-rich composition of the n = 2 member of the Bi 2 (Ca, Sr) n+1 Cu n O 2n+4 series has been investigated by neutron diffraction profile analysis. The results suggest that the Amaa space group may be more appropriate than the Fmmm space group.

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Neutron diffraction study of the structural changes in the antifluorite crystals Rb2PtI6, (NH4)2PtBr6, and (NH4)2PtI6

Canadian Journal of Physics ◽

10.1139/p81-056 ◽

1981 ◽

Vol 59 (3) ◽

pp. 449-456 ◽

Cited By ~ 20

Author(s):

Mark Sutton ◽

Robin L. Armstrong ◽

Brian M. Powell ◽

William J. L. Buyers

Keyword(s):

Phase Transitions ◽

Neutron Diffraction ◽

Diffraction Study ◽

Structural Changes ◽

Profile Analysis ◽

Structural Phase ◽

Neutron Diffraction Study ◽

Tetragonal Distortion ◽

Structural Phase Transitions

A neutron diffraction study of the structural phase transitions in Rb2PtI6, (NH4)2PtBr6, and (NH4)2PtI6 is presented. Cubic antifluorites studied to date exhibit transitions involving ferro- or antiferro-rotations of the halide octahedra with little or no tetragonal distortions. In this study we show that tetragonal distortions also occur in the antifluorites with or without accompanying rotations. Profile analysis reveals that below 65 K the Rb2PtI6 structure and below 50 K the (NH4)2PtBr6 structure become tetragonal with no evidence for rotation of the octahedra. Further, the 258 K transition in (NH4)2PtI6 is antiferro-rotative, with octahedra in successive (001) planes rotated in opposite senses, accompanied by a tetragonal distortion; the transition at 100 K involves a further ferro-rotation.

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