Twinning on pyramidal planes in hexagonal close packed crystals determined along with other defects by X-ray line profile analysis

2009 ◽  
Vol 42 (4) ◽  
pp. 580-591 ◽  
Author(s):  
Levente Balogh ◽  
Géza Tichy ◽  
Tamás Ungár
Keyword(s):  
Crystallite Size ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
Slip Systems ◽  
Line Broadening ◽  
X Ray ◽  
Hexagonal Close Packed ◽  
Dislocation Densities ◽  
Different Temperatures ◽  
Active Slip

A systematic procedure is developed to evaluate the frequency of {10.1}〈10.\overline 2〉 and {11.2}〈11.\overline 3〉 compressive twins and {10.2}〈10.\overline 1〉 and {11.1}〈\overline 1\overline 1.6〉 tensile twins together with dislocation densities, active slip systems and crystallite size in hexagonal close packed (hcp) metals. The effect of pyramidal twinning on X-ray line broadening in hcp metals is fundamentally different from the effect of twinning on close packed planes in face centred cubic (fcc) crystals. Therefore, the usual theoretical descriptions developed previously for fcc crystals cannot be used for pyramidal twinning in hcp crystals. The profile functions of sub-reflections for this type of twinning are derived to be the sum of a symmetrical and an antisymmetrical Lorentzian function. Sub-profile properties are parameterized and the parameter files are incorporated into the convolutional multiple whole profile (CMWP) procedure. The extended procedure,eCMWP, is applied to determine pyramidal twin frequencies together with dislocation densities, active slip systems and crystallite size in Mg deformed at different temperatures, in commercial purity Ti deformed at high temperature and in high-purity Ti deformed at room temperature.

Dislocation densities and crystallite size distributions in nanocrystalline ball-milled fluorides,MF2(M= Ca, Sr, Ba and Cd), determined by X-ray diffraction line-profile analysis

2005 ◽  
Vol 38 (6) ◽  
pp. 912-926 ◽  
Author(s):  
G. Ribárik ◽  
N. Audebrand ◽  
H. Palancher ◽  
T. Ungár ◽  
D. Louër
Keyword(s):  
Crystallite Size ◽  
Line Profile ◽  
Interference Effect ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
Size Distributions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Line Profile ◽  
Dislocation Densities

The dislocation densities and crystallite size distributions in ball-milled fluorides,MF2(M= Ca, Sr, Ba and Cd), of the fluorite structure type have been determined as a function of milling time by X-ray diffraction line-profile analysis. The treatment has been based on the concept of dislocation contrast to explain strain anisotropy by means of the modified Williamson–Hall and Warren–Averbach approaches and a whole-profile fitting method using physically based functions. In most cases, the measured and calculated patterns are in perfect agreement; however, in some specific cases, the first few measured profiles appear to be narrower than the calculated ones. This discrepancy is interpreted as the result of an interference effect similar to that described by Rafaja, Klemm, Schreiber, Knapp & Kužel [J. Appl. Cryst.(2004),37, 613–620]. By taking into account and correcting for this interference effect, the microstructure of ball-milled fluorides is determined in terms of dislocation structure and size distributions of coherent domains. A weak coalescence of the crystallites is observed at longer milling periods. An incubation period in the evolution of microstrains is in correlation with the homologous temperatures of the fluorides.

Dislocation densities and prevailing slip-system types determined by X-ray line profile analysis in a textured AZ31 magnesium alloy deformed at different temperatures

2013 ◽  
Vol 46 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Bertalan Jóni ◽  
Talal Al-Samman ◽  
Sandip Ghosh Chowdhury ◽  
Gábor Csiszár ◽  
Tamás Ungár
Keyword(s):  
Magnesium Alloy ◽  
Tensile Deformation ◽  
Profile Analysis ◽  
High Angular Resolution ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dislocation Densities ◽  
Different Temperatures ◽  
Diffraction Patterns

Tension experiments were carried out at room temperature, 473 K and 673 K on AZ31-type extruded magnesium alloy samples. The tensile deformation has almost no effect on the typical extrusion texture at any of the investigated temperatures. X-ray diffraction patterns provided by a high-angular-resolution diffractometer were analyzed for the dislocation density and slip activity after deformation to fracture. The diffraction peaks were sorted into two groups corresponding either to the major or to the random texture components in the specimen. The two groups of reflections were evaluated simultaneously as if the two texture components were two different phases. The dislocation densities in the major texture components are found to be always larger than those in the randomly oriented grain populations. The overwhelming fraction of dislocations prevailing in the samples is found to be of 〈a〉 type, with a smaller fraction of 〈c + a〉-type dislocations. The fraction of 〈c〉-type dislocations is always obtained to be zero within experimental error.

Twinning, Dislocations and Grain Size in NanoSPD Materials Determined by X-Ray Diffraction

2008 ◽  
Vol 584-586 ◽  
pp. 571-578 ◽  
Author(s):  
Tamás Ungár ◽  
L. Balogh ◽  
Gábor Ribárik
Keyword(s):  
Line Profile ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Systematic Analysis ◽  
Planar Defects ◽  
X Ray ◽  
Dislocation Densities ◽  
And Shifts

High resolution X-ray line profile analysis is sensitive to crystallite size, dislocation densities and character, and to planar defects, especially stacking faults or twinning. The different effects of microstructure features can be evaluated separately on the basis of the different corresponding profile functions and the different hkl dependences of line broadening. Profiles of faulted crystals consist of sub-profiles broadened and shifted according to different hkl conditions. The systematic analysis of the breadts and shifts of sub-profiles enables X-ray line profile analysis by using defect related profile functions corresponding to: (i) size, (ii) strain and (iii) planar faults, respectively. It is shown that twinning can either be enhanced or weakened by severe plastic deformation.

scholarly journals Investigations on Microstructural and Layer Disorder Parameters of Na-Montmorillonite-Glycine Intercalation Compounds

2012 ◽  
Vol 60 (1) ◽  
pp. 25-29 ◽  
Author(s):  
Adnan Hossain Khan ◽  
Parimal Bala ◽  
AFM Mustafizur Rahman ◽  
Mohammad Nurnabi
Keyword(s):  
Crystallite Size ◽  
Chain Length ◽  
Line Profile ◽  
Profile Analysis ◽  
Interlayer Spacing ◽  
Line Profile Analysis ◽  
X Ray ◽  
Microstructural Parameters ◽  
Silicate Layers ◽  
Layer Disorder

Glycine-Montmorillonite (Gly-MMT) composite has been synthesized through intercalation process using Na-Montmorillonite (Na- MMT) and glycine ethylester hydrochloride. Gly-MMT was employed for the synthesis of dipeptide (Gly-Gly-MMT). Microstructural parameters such as crystallite size, r.m.s. strain (<e2>1/2) and layer disorder parameters such as variation of interlayer spacing (g) and proportion of planes affected by such defects (?) of the samples have been calculated by X-ray line profile analysis. In comparison to Na-MMT the basal spacings (d001) of Gly-MMT and Gly-Gly-MMT were reduced by 2.4Å and 1.8Å respectively. The value of d001 of Gly-Gly-MMT (13.3 Å) suggests the monolayer orientation of dipeptide into interlayer spaces. It is also suggested that more homogeneity in the stacking of silicate layers is attained in Gly-Gly-MMT due to the increased chain length of the dipeptide and orientation in monolayer style.DOI: http://dx.doi.org/10.3329/dujs.v60i1.10331Dhaka Univ. J. Sci. 60(1): 25-29, 2012 (January)

scholarly journals Influence of sintering temperature and pressure on crystallite size and lattice defect structure in nanocrystalline SiC

2007 ◽  
Vol 22 (5) ◽  
pp. 1314-1321 ◽  
Author(s):  
J. Gubicza ◽  
S. Nauyoks ◽  
L. Balogh ◽  
J. Labar ◽  
T.W. Zerda ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Defect Structure ◽  
Sintering Temperature ◽  
Profile Analysis ◽  
Lattice Defect ◽  
Line Profile Analysis ◽  
Crystallite Growth ◽  
X Ray ◽  
Transmission Electron ◽  
Temperature And Pressure

Microstructure of sintered nanocrystalline SiC is studied by x-ray line profile analysis and transmission electron microscopy. The lattice defect structure and the crystallite size are determined as a function of pressure between 2 and 5.5 GPa for different sintering temperatures in the range from 1400 to 1800 °C. At a constant sintering temperature, the increase of pressure promotes crystallite growth. At 1800 °C when the pressure reaches 8 GPa, the increase of the crystallite size is impeded. The grain growth during sintering is accompanied by a decrease in the population of planar faults and an increase in the density of dislocations. A critical crystallite size above which dislocations are more abundant than planar defects is suggested.

Dislocation Densities in Dispersion-Strengthened Copper with Aluminum Oxide from X-Ray Line Profile Analysis

2018 ◽  
Vol 941 ◽  
pp. 2024-2029
Author(s):  
Mutsumi Sano ◽  
Sunao Takahashi ◽  
Atsuo Watanabe ◽  
Ayumi Shiro ◽  
Takahisa Shobu ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Aluminum Oxide ◽  
Ambient Temperature ◽  
Line Profile ◽  
Profile Analysis ◽  
Compressive Strain ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dislocation Densities

Dislocation densities of dispersion-strengthened copper with aluminum oxide, namely GlidCop were evaluated employing the X-ray line profile analysis using the modified Williamson-Hall and modified Warren-Averbach method. X-ray diffraction profiles for GldCop samples with compressive strains applied at ambient temperature were measured with synchrotron radiation. The dislocation densities of GlidCop with compressive strain ranging from 0 – 2.7 % were on the order of 1.5×1014 – 6.6×1014 m-2.

Microstructural parameters and layer disorder accompanying dehydration transformation in Na-montmorillonite

2000 ◽  
Vol 215 (4) ◽  
Author(s):  
S.K. Srivastava ◽  
P. Bala ◽  
B.K. Samantaray ◽  
Hartmut Haeuseler
Keyword(s):  
Crystallite Size ◽  
Structural Changes ◽  
Profile Analysis ◽  
Thermal Transformation ◽  
Initial Slope ◽  
Line Profile Analysis ◽  
Line Profiles ◽  
X Ray ◽  
Microstructural Parameters ◽  
Layer Disorder

Structural changes accompanying thermal transformation in Na-montmorillonite samples up to a temperature of 500°C have been investigated by X-ray line profile analysis. The method of Fourier initial slope and variance analysis of X-ray line profiles have been used to calculate the different microstructural parameters like crystallite size, r.m.s. strain (<e

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