scholarly journals Subgrain size-distributions, dislocation structures, stacking- and twin faults and vacancy concentrations in crystalline materials determined by X-ray line profile analysis

2005 ◽  
Vol 61 (a1) ◽  
pp. c78-c78
Author(s):  
T. Ungár
Keyword(s):  
Line Profile ◽  
Profile Analysis ◽  
Subgrain Size ◽  
Line Profile Analysis ◽  
Size Distributions ◽  
Crystalline Materials ◽  
X Ray ◽  
Vacancy Concentrations

Subgrain Size-Distributions, Dislocation Structures, Stacking- and Twin Faults and Vacancy Concentrations in SPD Materials Determined by X-Ray Line Profile Analysis

2006 ◽  
Vol 503-504 ◽  
pp. 133-140 ◽  
Author(s):  
Tamás Ungár
Keyword(s):  
Plastic Deformation ◽  
Line Profile ◽  
Profile Analysis ◽  
Subgrain Size ◽  
Stacking Faults ◽  
Line Profile Analysis ◽  
Size Distributions ◽  
X Ray ◽  
The Status ◽  
Vacancy Concentrations

The fundamentals of X-ray line profile analysis are summarised in terms of subgrain size and size-distribution, dislocation density and dislocation types, especially edge and screw dislocations, intrinsic and extrinsic stacking faults and twin boundaries and vacancies produced during plastic deformation. It is shown that deformation induced vacancy concentrations in the grain boundaries of compressed copper polycrystals are close to the equilibrium values at the melting temperature. The discrepancy between X-ray and TEM size values is discussed in terms subgrain- and grain size. It is shown that this apparent discrepancy might be used to determine the status of fragmentation by severe plastic deformation.

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.

scholarly journals Microstructure Characterization in Individual Texture Components by X-Ray Line Profile Analysis: Principles of the X-TEX Method and Practical Application to Tensile-Deformed Textured Ti

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 691
Author(s):  
Bertalan Jóni ◽  
Éva Ódor ◽  
Mia Maric ◽  
Wolfgang Pantleon ◽  
Tamás Ungár
Keyword(s):  
Line Profile ◽  
Profile Analysis ◽  
Subgrain Size ◽  
Pure Titanium ◽  
Evaluation Procedure ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dislocation Densities ◽  
Diffraction Peaks

A novel X-ray diffraction-based method and computer program X-TEX has been developed to determine the microstructure in individual texture components of polycrystalline, textured materials. Two different approaches are presented. In the first one, based on the texture of the specimen, the X-TEX software provides optimized specimen orientations for X-ray diffraction experiments in which diffraction peaks consist of intensity contributions stemming from grain populations of separate texture components in the specimen. Texture-specific diffraction patterns can be created by putting such peaks together from different measurements into an artificial pattern for each texture component. In the second one, the X-TEX software can determine the intensity contributions of different texture components to diffraction peaks measured in a particular sample orientation. According to this, peaks belonging mainly to one of the present texture components are identified and grouped into the same quasi-phase during the evaluation procedure. The X-TEX method was applied and tested on tensile-deformed, textured, commercially pure titanium samples. The patterns were evaluated by the convolutional multiple whole profile (CMWP) procedure of line profile analysis for dislocation densities, dipole character, slip systems and subgrain size for three different texture components of the Ti specimens. Significant differences were found in the microstructure evolution in the two major and the random texture components. The dislocation densities were discussed by the Taylor model of work hardening.

scholarly journals Characterization of defect structures in nanocrystalline materials by X-ray line profile analysis

2007 ◽  
Vol 222 (11/2007) ◽  
Author(s):  
Jenõ Gubicza ◽  
Tamás Ungár
Keyword(s):  
Line Profile ◽  
Nanocrystalline Materials ◽  
Profile Analysis ◽  
Subgrain Size ◽  
Line Profile Analysis ◽  
Line Broadening ◽  
X Ray ◽  
Transmission Electron ◽  
Fitting Procedures ◽  
Dislocation Type

X-ray line profile analysis is a powerful alternative tool for determining dislocation densities, dislocation type, crystallite and subgrain size and size-distributions, and planar defects, especially the frequency of twin boundaries and stacking faults. The method is especially useful in the case of submicron grain size or nanocrystalline materials, where X-ray line broadening is a well pronounced effect, and the observation of defects with very large density is often not easy by transmission electron microscopy. The fundamentals of X-ray line broadening are summarized in terms of the different qualitative breadth methods, and the more sophisticated and more quantitative whole pattern fitting procedures. The efficiency and practical use of X-ray line profile analysis is shown by discussing its applications to metallic, ceramic, diamond-like and polymer nanomaterials.

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