scholarly journals Microstrain Measurement in Plastically Deformed Austenitic Steel

1999 ◽  
Vol 33 (1-4) ◽  
pp. 219-230 ◽  
Author(s):  
K. Hirschi ◽  
M. Ceretti ◽  
P. Lukás ◽  
N. Ji ◽  
C. Braham ◽  
...  
Keyword(s):  
Austenitic Steel ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compressive Stresses ◽  
Cold Rolled ◽  
The Mean ◽  
Good Agreement

Some results of high-resolution neutron diffraction experiments resulting in determination of the microstrain in metallic materials are reported. The method of the diffraction line broadening analysis was verified in two materials, investigated earlier by X-ray diffraction: an austenitic steel prestrained up to 30% and a cold rolled aluminium magnesium alloy. For these materials, the mean-square microstrain and the dislocation density were determined, a good agreement was reached with the results of X-ray experiments. As an application of such analysis we investigated the influence of the shot-peening treatment on an austenitic steel. This treatment is commonly used to introduce compressive stresses in the surface of material, giving improved resistance to fatigue fracture. The microstrain distribution and the size of coherently diffracting blocks for a shot-peened sample of austenitic steel as a function of depth from the surface are determined by the above analysis and the results are presented.

Investigation of Residual Strains of the Second Kind in Plastically Deformed Metallic Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
M. Vrána ◽  
P. Klimanek ◽  
T. Kschidock ◽  
P. Lukáš ◽  
P. Mikula
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Stacking Faults ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Residual Strains ◽  
Good Agreement

ABSTRACTInvestigation of strongly distorted crystal structures caused by dislocations, stacking-faults etc. in both plastically deformed f.c.c. and b.c.c. metallic materials was performed by the analysis of the neutron diffraction line broadening. Measurements were realized by means of the high resolution triple-axis neutron diffractometer equipped by bent Si perfect crystals as monochromator and analyzer at the NPI Řež. The substructure parameters obtained in this manner are in good agreement with the results of X-ray diffraction analysis.

The Use of the Pseudo-Voigt Function in the Variance Method of X-ray Line-Broadening Analysis

1997 ◽  
Vol 30 (4) ◽  
pp. 427-430 ◽  
Author(s):  
F. Sánchez-Bajo ◽  
F. L. Cumbrera
Keyword(s):  
Crystallite Size ◽  
Original Form ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Variance Method ◽  
The Mean ◽  
Voigt Function

A modified application of the variance method, using the pseudo-Voigt function as a good approximation to the X-ray diffraction profiles, is proposed in order to obtain microstructural quantities such as the mean crystallite size and root-mean-square (r.m.s.) strain. Whereas the variance method in its original form is applicable only to well separated reflections, this technique can be employed in the cases where there is line-profile overlap. Determination of the mean crystallite size and r.m.s. strain for several crystallographic directions in a nanocrystalline cubic sample of 9-YSZ (yttria-stabilized zirconia) has been performed by means of this procedure.

Phase analysis of sintered yttria–zirconia ceramics by x-ray diffraction

1986 ◽  
Vol 1 (2) ◽  
pp. 295-299 ◽  
Author(s):  
A. Paterson ◽  
R. Stevens
Keyword(s):  
Tetragonal Phase ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Zirconia Ceramics ◽  
X Ray ◽  
Different Temperatures ◽  
Shear Transformation ◽  
Original Amount ◽  
Good Agreement

Determination of the amount of cubic and tetragonal phase in yttria–zirconia using high-angle XRD (x-ray diffraction) has been complicated by problems of resolution and interpretation. The evidence, from electron diffraction studies, for a c→t shear transformation also needs to be taken into account. Two compositions, a 3 and a 5.7 mol % Y2O3−ZrO2, were sintered and thermally treated at different temperatures between 1450°and 1700°C. X-ray diffraction traces revealed the anticipated tetragonal (400) and (004) reflections. The region of the diffraction pattern that was thought to arise from the cubic phase could be best interpreted as a second tetragonal phase t'. The original amount of cubic phase computed from the t' reflections showed good agreement with the phase diagram of Scott. The lattice parameters of the t' phase were determined, and the volume of the tetragonal (t') unit cell was calculated.

The Determination of Crystallite Size and Size Distribution from Broadened X-Ray Diffraction Lines

1961 ◽  
Vol 5 ◽  
pp. 94-103 ◽  
Author(s):  
H. F. Quinn ◽  
P. Cherin
Keyword(s):  
Harmonic Analysis ◽  
Size Distribution ◽  
Fourier Coefficients ◽  
Distribution Functions ◽  
Composite Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mean Size ◽  
The Mean

AbstractMagnesium oxide crystallites having mean dimensions in the range of 25–1000 A can be prepared by controlled thermal decomposition of the carbonate.Following some earlier investigations of Birks and Friedman, we have determined the mean size and size distribution of several such MgO samples from the broadened X-ray diffraction lines which they exhibit. Contrary to the procedure of the above investigators, the harmonic analysis due to Stokes has been used to correct for instrumental broadening and values of mean-size and size-distribution functions obtained from the Fourier coefficients by the methods of Warren and Averbach.The results obtained are compared with average sizes and distributions obtained by direct examination of the samples in an electron microscope.A composite sample has been prepared by mixing known quantities of the sample previously studied. The distribution function obtained by harmonic analysis of one diffraction line of the composite sample is compared with the function calculated from the distributions of its components.Conclusions are drawn concerning the significance of the results obtained by the Warren technique: in particular, the average sizes obtained by this method are compared with those given by the approximate method used by Birks and Friedman.

Bismuth on GaSb(110): Structural Determination of the 1×1 and 1×2 Phases by Surface X-Ray Diffraction

1998 ◽  
Vol 05 (05) ◽  
pp. 1043-1052 ◽  
Author(s):  
L. Lottermoser ◽  
T. Van Gemmeren ◽  
O. Bunk ◽  
R. L. Johnson ◽  
E. Landemark ◽  
...  
Keyword(s):  
Structural Model ◽  
Layer Structure ◽  
Zigzag Chain ◽  
X Ray Diffraction ◽  
Surface Geometry ◽  
X Ray ◽  
Reconstructed Surface ◽  
Thermal Stability Of ◽  
Good Agreement

The surface geometry of the 1×1 and 1×2 phases of bismuth on GaSb(110) has been determined using surface X-ray diffraction with synchrotron radiation. The bismuth atoms form zigzag chains along the [Formula: see text] direction of the substrate. For the 1×1 phase four different registries of the bismuth chains with respect to the GaSb(110) substrate are possible. It was found that only the epitaxial continued layer structure was in good agreement with the experimental data. In the 1×2 reconstruction every second zigzag chain in the uppermost substrate layer is missing. The reconstructed surface is terminated with a full monolayer of Bi atoms which also form zigzag chains. The Bi atoms in the chains bond alternately to the first and second layer substrate atoms and the Bi chains are inclined at 34° to the surface. This new structural model explains the higher thermal stability of the 1×2 phase compared to that of the 1×1 phase.

A method for the interpretation of the Warren–Averbach mean-squared strains and its application to recovery in aluminium

1983 ◽  
Vol 16 (2) ◽  
pp. 176-182 ◽  
Author(s):  
M. J. Turunen ◽  
Th. de Keijser ◽  
R. Delhez ◽  
N. M. van. der. Pers
Keyword(s):  
Strain Curve ◽  
Local Strain ◽  
Diffraction Line ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Strain Fields ◽  
X Ray ◽  
The Mean ◽  
Derivatives Of

A method for the interpretation of Warren–Averbach mean-squared strain curves is presented. If a polynomial is fitted to such a mean-squared strain curve, then the coefficients of this polynomial can be expressed simply in the mean-squared local strain in the direction perpendicular to the diffracting planes and the mean-squared derivatives of this strain. The method is applied to a series of X-ray diffraction line broadening measurements of isochronally recovery-annealed aluminium. The changes in the average squared derivatives observed after different anneals are explained as changes in the dislocation arrangements in the specimen. The parameters obtained by the method are found to be sensitive to small changes in the strain fields.

scholarly journals Theoretical and experimental determination of mass attenuation coefficients of lead-based ceramics and their comparison with simulation

2016 ◽  
Vol 31 (2) ◽  
pp. 142-149 ◽  
Author(s):  
Alireza Vejdani-Noghreiyan ◽  
Elham Aliakbari ◽  
Atiyeh Ebrahimi-Khankook ◽  
Mahdi Ghasemifard
Keyword(s):  
Gamma Ray ◽  
Mass Attenuation Coefficient ◽  
X Ray Diffraction ◽  
Attenuation Coefficients ◽  
X Ray ◽  
Simulation Results ◽  
Theoretical Results ◽  
Good Agreement ◽  
Mass Attenuation

Mass attenuation coefficient of lead-based ceramics have been measured by experimental methods and compared with theoretical and Monte Carlo simulation results. Lead-based ceramics were prepared using mixed oxide method and the X-ray diffraction analysis was done to evaluate the crystal structure of the produced handmade ceramics. The experimental results show good agreement with theoretical and simulation results. However at two gamma ray energies, small differences between experimental and theoretical results have been observed. By adding other additives to ceramics and observing the changes in the shielding properties such as flexibility, one can synthesize and optimize ceramics as a neutron shield.

The Molecular Structure and Hydrogen Bond Geometry in Liquid Formamide: Electron, Neutron, and X-Ray Diffraction Studies

1983 ◽  
Vol 38 (2) ◽  
pp. 231-236 ◽  
Author(s):  
E. Kálmán ◽  
I. Serke ◽  
G. Pálinkás ◽  
M. D. Zeidler ◽  
F. J. Wiesmann ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Hydrogen Bond ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Free Molecule ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Mean ◽  
Diffraction Patterns ◽  
Good Agreement

Abstract Electron, neutron and X-ray diffraction patterns of liquid formamide have been measured at a temperature of 25 °C. Analysis of the diffraction data yields the molecular structure and the average geometry of the hydrogen bond. The molecular parameters obtained from liquid diffraction experiments are in good agreement with those from gas electron diffraction for the free molecule. The mean O…N and O…H hydrogen bond distances are 2.9 Å and 1.9 Å, respectively. Four H-bonds per molecule are found on the average. The deviation of the H-bonds from the linearity is estimated.

Automatic determination of diffuse-peak positions and the centre of a diffraction pattern

1999 ◽  
Vol 32 (2) ◽  
pp. 332-335 ◽  
Author(s):  
S. J. Wilkinson ◽  
D. W. L. Hukins
Keyword(s):  
Annulus Fibrosus ◽  
Gaussian Function ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oriented Molecules ◽  
Beam Stop ◽  
Diffraction Patterns ◽  
Good Agreement

Correlation with a two-dimensional Gaussian function was used to locate the positions of diffuse peaks in X-ray diffraction patterns. The centre of a pattern was defined as the centroid of the image of the undeflected beam, found by convolution with a two-dimensional Gaussian function. These methods were implemented using the IDL programing language. They were tested on diffraction patterns from systems containing oriented molecules of the protein collagen: collagen tape, elastoidin spicules and annulus fibrosus of intervertebral disc. Specimens were dusted with quartz to calibrate the diffraction patterns. These patterns were recorded on film, using a semi-transparent beam stop to obtain an image of the undeflected beam, and digitized at a resolution of 105 µm. Intermolecular spacings, calculated from the distance between a peak and the centre of a pattern, were in good agreement with those determined previously.

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