General Consideration of the Loss of Information on the Orientation Distribution Function of Texturized Samples in Pole Figure Measurements

1982 ◽  
Vol 113 (2) ◽  
pp. 569-582 ◽  
Author(s):  
S. Matthies ◽  
K. Helming
2012 ◽  
Vol 27 (2) ◽  
pp. 114-116 ◽  
Author(s):  
Thomas Gnäupel-Herold

A software for the calculation of diffraction elastic constants (DEC) for materials both with and without preferred orientation was developed. All grain-interaction models that can use the crystallite orientation distribution function (ODF) are incorporated, including Kröner, Hill, inverse Kröner, and Reuss. The functions of the software include: reading the ODF in common textual formats, pole figure calculation, calculation of DEC for different (hkl,φ,ψ), calculation of anisotropic bulk constants from the ODF, calculation of macro-stress from lattice strain and vice versa, as well as mixture ratios of (hkl) of overlapped reflections in textured materials.


1989 ◽  
Vol 10 (3) ◽  
pp. 243-264 ◽  
Author(s):  
A. Morawiec ◽  
J. Pospiech

The relationship between the orientation distribution function (ODF) and the pole figure is based on the geometry of projection lines in the orientation space.The paper presents an analytical description of the projection lines and their transformations by symmetry operations. Using simple algebraical rules some properties of the projection lines as well as some properties of the associated projection lines (coupled due to the centrosymmetry of the pole figure) have been derived.


1982 ◽  
Vol 5 (2) ◽  
pp. 87-94 ◽  
Author(s):  
H. J. Bunge ◽  
C. Esling

The orientation distribution function of a textured polycrystalline material may be split into an even and odd part; the latter is not reproducible from pole figure measurements as has been recently shown. The class of textures containing only a reproducible part is considered. In the case of axially symmetric textures (fibre textures), these take on a very simple form. They are, however, not the only type of reproducible textures as has been assumed. A sample having a reproducible texture is centrosymmetric, even in the most general case of non-centrosymmetric, enantiomorphic crystals of one crystal form only. Symmetry elements of this kind have been called non-conventional ones. They may be described by black-and-white or Shubnikov groups. Reproducible textures correspond to a non-conventional centre of inversion as an element of sample symmetry and vice versa.


1995 ◽  
Vol 28 (5) ◽  
pp. 532-533 ◽  
Author(s):  
L.-G. Yu ◽  
H. Guo ◽  
B. C. Hendrix ◽  
K.-W. Xu ◽  
J.-W. He

A new simple method is proposed for determining the orientation distribution function (ODF) for three-dimensional texture analysis in a polycrystal based on the reality that the accuracy of an ODF is dependent on both the accuracy of each measured pole figure and the number of pole figures.


1995 ◽  
Vol 28 (5) ◽  
pp. 527-531 ◽  
Author(s):  
L.-G. Yu ◽  
H. Guo ◽  
B. C. Hendrix ◽  
K.-W. Xu ◽  
J.-W. He

The sources of indefiniteness in the orientation-distribution-function (ODF) description of crystalline texture are shown to result from the integral nature of the pole-figure measurement. An equipartition-area theorem is proved and it is shown that current methods use too few pole figures, which are measured to an unnecessarily high angular resolution. The experimental resolution is considered and the number of pole figures needed for ODF analysis is calculated as a function of the required ODF resolution.


1982 ◽  
Vol 5 (2) ◽  
pp. 73-86 ◽  
Author(s):  
János Imhof

The values of the orientation distribution function and the data of the pole-figure are correlated by products of particular conditional probabilities. One of the possible approximations of these products are obtained and demonstrated with the help of an example showing how the orientation distribution function can thus be obtained.


1982 ◽  
Vol 4 (4) ◽  
pp. 189-200 ◽  
Author(s):  
János Imhof

The orientation distribution function depends on the measured pole-figure data structure. With reference to the divisions of the pole-figure the orientation space is divided into classes, such that contain orientations indistinguishable on the basis of pole-figure data. These classes should refer to distinguishable values of the orientation distribution function. Divisions of orientation space are considered in formulating the fundamental equation of texture analysis. Probabilistic interpretation of the fundamental equation is formulated.


2018 ◽  
Vol 51 (3) ◽  
pp. 895-900 ◽  
Author(s):  
Shigehiro Takajo ◽  
Sven C. Vogel

The coverage of a given diffraction instrument as a percentage of the area 2π of a pole figure hemisphere is a crucial parameter of each diffraction instrument used for texture or strain pole figure determination. On the basis of this knowledge, the number of rotations and rotation angles for a full determination of the orientation distribution function can be optimized. However, the determination of this quantity is non-trivial. This paper presents a method that projects a given detector coverage into pole figure space, i.e. outlines the detector areas in a pole figure, and then determines the fraction of the entire 2π pole figure hemisphere around the sample that is covered. The freely available Generic Mapping Tools (GMT) and ImageJ are utilized for this quantification. With this method, it is shown that the empirically determined rotation angles for the HIPPO neutron time-of-flight diffractometer are close to optimal for a set of three rotations.


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