Anomalous X-ray diffraction from ω nanoparticles in β-Ti(Mo) single crystals

2019 ◽  
Vol 75 (5) ◽  
pp. 718-729 ◽  
Author(s):  
Jana Šmilauerová ◽  
Petr Harcuba ◽  
Miroslav Cieslar ◽  
Miloš Janeček ◽  
Václav Holý
Keyword(s):  
Titanium Alloy ◽  
Absorption Edge ◽  
Beam Energy ◽  
Diffuse Scattering ◽  
Atomic Orbital ◽  
Primary Beam ◽  
Scattered Intensity ◽  
Diffraction Maximum ◽  
X Ray Diffraction ◽  
X Ray

Anomalous X-ray diffraction (AXRD) is a technique which makes use of effects occurring near the energy of an absorption edge of an element present in the studied sample. The intensity of the diffracted radiation exhibits an anomalous decrease when the primary beam energy matches the energy needed to excite an electron from an atomic orbital. The characteristics of this step are sensitive to the concentration of the `anomalous' element and its spatial distribution in the sample. In the present investigation, AXRD was employed to study ω particles in a metastable β titanium alloy Ti–15Mo (in wt%). The experiments were done in an energy range around the Mo K edge at 20.0 keV, allowing investigation of the distribution of Mo in the material, which is rejected from the volume of ω particles during their diffusion-driven growth. This paper deals with diffuse scattering patterns around the (006)β diffraction maximum. It was observed that different regions of the diffuse scattering exhibited different variations of diffracted intensity with the incident photon energy near the absorption edge. Numerical simulations of diffuse scattering patterns as well as of energy dependences of the scattered intensity were performed. It was found that the observed patterns and their dependence on the primary beam energy can be explained by taking into account (a) elastic deformation of the β matrix arising from the presence of slightly misfitting ω particles and (b) the presence of a `cloud' of a higher Mo concentration around ω particles.

scholarly journals A study of deformation twinning in a titanium alloy by X-ray diffraction contrast tomography

2016 ◽  
Vol 105 ◽  
pp. 417-428 ◽  
Author(s):  
Laura Nervo ◽  
Andrew King ◽  
Arnas Fitzner ◽  
Wolfgang Ludwig ◽  
Michael Preuss
Keyword(s):  
Titanium Alloy ◽  
Deformation Twinning ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Contrast

scholarly journals Atomic structure and phason modes of the Sc–Zn icosahedral quasicrystal

IUCrJ ◽  
2016 ◽  
Vol 3 (4) ◽  
pp. 247-258 ◽  
Author(s):  
Tsunetomo Yamada ◽  
Hiroyuki Takakura ◽  
Holger Euchner ◽  
Cesar Pay Gómez ◽  
Alexei Bosak ◽  
...  
Keyword(s):  
Atomic Structure ◽  
Diffuse Scattering ◽  
Waller Factor ◽  
Close Packing ◽  
Icosahedral Quasicrystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Large Atom ◽  
Debye Waller Factor ◽  
The Difference

The detailed atomic structure of the binary icosahedral (i) ScZn7.33quasicrystal has been investigated by means of high-resolution synchrotron single-crystal X-ray diffraction and absolute scale measurements of diffuse scattering. The average atomic structure has been solved using the measured Bragg intensity data based on a six-dimensional model that is isostructural to the i-YbCd5.7one. The structure is described with a quasiperiodic packing of large Tsai-type rhombic triacontahedron clusters and double Friauf polyhedra (DFP), both resulting from a close-packing of a large (Sc) and a small (Zn) atom. The difference in chemical composition between i-ScZn7.33and i-YbCd5.7was found to lie in the icosahedron shell and the DFP where in i-ScZn7.33chemical disorder occurs on the large atom sites, which induces a significant distortion to the structure units. The intensity in reciprocal space displays a substantial amount of diffuse scattering with anisotropic distribution, located around the strong Bragg peaks, that can be fully interpreted as resulting from phason fluctuations, with a ratio of the phason elastic constantsK2/K1= −0.53,i.e.close to a threefold instability limit. This induces a relatively large perpendicular (or phason) Debye–Waller factor, which explains the vanishing of `high-Qperp' reflections.

PHYSICAL PROPERTIES AND MICROSTRUCTURE PERFORMANCE OF LASER ALLOYING Zn MODIFIED AMORPHOUS-NANOCRYSTALS REINFORCED COATING

NANO ◽  
2013 ◽  
Vol 08 (04) ◽  
pp. 1350038 ◽  
Author(s):  
JIANQUAN LI ◽  
HUASHI LIU ◽  
JIANING LI ◽  
GUOZHONG LI
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Electron Microscope ◽  
Crystallization Process ◽  
Laser Alloying ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Phases ◽  
Transmission Electron ◽  
Improve Wear Resistance

Zn was firstly used to improve wear resistance of a TA7 (Ti–5Al–2.5Sn) titanium alloy surface by mean of a laser alloying (LA) technique. The synthesis of the hard coating on a TA7 titanium alloy by LA of Co–Ti–Cr–TiB2–Zn–CeO2 pre-placed powders was investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM). Experimental results indicated lot of the nanocrystals, such as Ti–B/CoZn13 and the amorphous phases were produced in such LA coating. The nucleation and growth of the amorphous phases were retarded by the nanocrystals in a certain extent during the crystallization process of the amorphous phases. Compared with a TA7 alloy substrate, an improvement of the wear resistance was obtained for such LA composite coating.

Crystal structure and enantiomeric layer disorder of a copper(I) nitrate π-coordination compound

2021 ◽  
Vol 77 (2) ◽  
Author(s):  
Dorota A. Kowalska ◽  
Vasyl Kinzhybalo ◽  
Yuriy I. Slyvka ◽  
Marek Wołcyrz
Keyword(s):  
Coordination Compound ◽  
Local Structure ◽  
Diffuse Scattering ◽  
Weak Interactions ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Solution ◽  
First Time ◽  
Layer Disorder

The novel π-coordination compound [CuI(m-dmphast)NO3], where m-dmphast = 5-(allylthio)-1-(3,5-dimethylphenyl)-1H-tetrazole, is characterized using single-crystal X-ray diffraction and crystallizes in a noncentrosymmetric space group. Additionally, for the first time in this group of materials, the streaks of X-ray diffuse scattering in the reciprocal space sections were observed and described. This gave the possibility for a deeper insight into the local structure of the title compound. The conjecture about the origin of diffuse scattering was derived from average structure solution. It was then confirmed using the local structure modelling. The extended [Cu(m-dmphast)NO3]∞ chains, connected by weak interactions, produce layers which can exist in two enantiomeric forms, one of which predominates.

In situ characterizations of phase transformations kinetics in the Ti17 titanium alloy by electrical resistivity and high temperature synchrotron X-ray diffraction

2008 ◽  
Vol 476 (1-2) ◽  
pp. 60-68 ◽  
Author(s):  
Fabien Bruneseaux ◽  
Elisabeth Aeby-Gautier ◽  
Guillaume Geandier ◽  
Julien Da Costa Teixeira ◽  
Benoît Appolaire ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Titanium Alloy ◽  
High Temperature ◽  
Phase Transformations ◽  
X Ray Diffraction ◽  
X Ray

X-Ray Diffuse Scattering Investigation of Defects in Ion Implanted and Annealed Silicon

1998 ◽  
Vol 524 ◽  
Author(s):  
C. H. Chang ◽  
U. Beck ◽  
T. H. Metzger ◽  
J. R. Patel
Keyword(s):  
Ion Implantation ◽  
Point Defect ◽  
Point Defects ◽  
Diffuse Scattering ◽  
Grazing Incidence ◽  
X Rays ◽  
Scattered Intensity ◽  
X Ray ◽  
Defect Clusters ◽  
Point Defect Clusters

ABSTRACTTo characterize the point defects and point defect clusters introduced by ion implantation and annealing, we have used grazing incidence x-rays to measure the diffuse scattering in the tails of Bragg peaks (Huang Scattering). An analysis of the diffuse scattered intensity will allow us to characterize the nature of point defects or defect clusters introduced by ion implantation. We have also observed unexpected satellite peaks in the diffuse scattered tails. Possible causes for the occurrence of the peaks will be discussed.

Multiple-wavelength powder diffraction using imaging plates at the Australian National Beamline

1998 ◽  
Vol 5 (3) ◽  
pp. 926-928 ◽  
Author(s):  
David J. Cookson ◽  
Brett A. Hunter ◽  
Shane J. Kennedy ◽  
Richard F. Garrett
Keyword(s):  
Copper Oxide ◽  
Powder Diffraction ◽  
Absorption Edge ◽  
Diffraction Data ◽  
Beam Energy ◽  
Powder Diffraction Data ◽  
Multiple Exposure ◽  
X Ray ◽  
Multiple Wavelength ◽  
Imaging Plates

The Australian powder diffractometer at the Photon Factory is capable of recording multiple powder-diffraction scans in less than 5 min per pattern using imaging plates in Debye–Scherrer geometry. This, coupled with incrementing the X-ray beam energy in suitably small steps (down to ∼2 eV) between exposures, allows fast collection of anomalous diffraction data. Data collected from a copper oxide-based superconductor at energies near the Cu K-absorption edge are presented, along with an account of the technique used to extract multiple-exposure powder-diffraction data from imaging plates.

Crystallization Process and Chemical Disorder in Flash Evaporated Amorphous Gallium Antimonide Films

1993 ◽  
Vol 321 ◽  
Author(s):  
J. H. Dias Da Silva ◽  
I. Cisneros ◽  
L. P. Cardoso
Keyword(s):  
Optical Absorption ◽  
Absorption Edge ◽  
Gallium Antimonide ◽  
Crystallization Process ◽  
Optical Absorption Edge ◽  
X Ray Diffraction ◽  
Flash Evaporation ◽  
X Ray ◽  
Local Ordering ◽  
Chemical Disorder

ABSTRACTIn this work we describe a flash evaporation system specially built to produce Amorphous films of III-V compounds and characterize GaSb films using optical, electrical and X-Ray diffraction Measurements. Changes in the composition of the GaSb samples were obtained by the use of different crucible temperatures. In such samples, consequently, the optical absorption edge and the DC electrical conductivity were Modified. The departure from stoichiometry in GaSb films is analyzed on the basis of these results which can be used as an evidence of the chemical disorder. This kind of disorder is represented by either wrong bonds or sites with different coordination.Thermal annealing with a sequence of increasing temperatures first induced detectable variations in the optical absorption edge and in the vibrational properties of the Amorphous GaSb. These variations are compatible with the GaSb local ordering and were observed by Raman scattering and infrared absorption spectra. The annealing at higher temperatures allowed the crystallization of the material confirmed by X-Ray diffraction. From these experimental results a crystallization mechanism based on the segregation of Sb excess coming from the crystallized regions toward the Amorphous tissue is proposed.

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