Critical evaluation of the Lotgering degree of orientation texture indicator

2004 ◽  
Vol 19 (11) ◽  
pp. 3414-3422 ◽  
Author(s):  
Jacob L. Jones ◽  
Elliott B. Slamovich ◽  
Keith J. Bowman
Keyword(s):  
Bismuth Titanate ◽  
Critical Evaluation ◽  
Orientation Distribution ◽  
X Ray Diffraction ◽  
Standard Unit ◽  
X Ray ◽  
Pole Figures ◽  
Textured Ceramics ◽  
Degree Of Orientation ◽  
Tape Cast

Preferred orientation in textured ceramics is often assessed by comparing the relative intensities of x-ray diffraction reflections to those of a randomly oriented ceramic using the Lotgering degree of orientation (f). However, this paper provides evidence that indiscriminate assessments of f can be misleading. Using measured intensities of a modestly textured tape cast bismuth titanate (Na0.5Bi4.5Ti4O15) ceramic, calculated f values vary from 7.4 to 73.2% depending on the reflections included in the calculation. The texture is also quantified by calculating the orientation distribution function (ODF) using measured pole figures. A model is then presented that demonstrates f is nonlinear with the multiple of preferred (00l)-orientations, the standard unit of the 00l pole figure.

Textures Applied to Mechanical Processing Technology Assessment in Ancient Bronze

2005 ◽  
Vol 495-497 ◽  
pp. 719-724
Author(s):  
R.E. Bolmaro ◽  
B. Molinas ◽  
E. Sentimenti ◽  
A.L. Fourty
Keyword(s):  
Orientation Distribution ◽  
Distribution Functions ◽  
Archaeological Sites ◽  
Mechanical Processing ◽  
Post Processing ◽  
X Ray Diffraction ◽  
Mechanical Process ◽  
X Ray ◽  
Pole Figures ◽  
Microscopic Inspection

Some ancient metallic art craft, utensils, silverware and weapons are externally undistinguishable from modern ones. Not only the general aspect and shape but also some uses have not changed through the ages. Moreover, when just some small pieces can be recovered from archaeological sites, the samples can not easily be ascribed to any known use and consequently identified. It is clear that mechanical processing has changed along history but frequently only a "microscopic" inspection can distinguish among different techniques. Some bronze samples have been collected from the Quarto d’Altino (Veneto) archaeological area in Italy (paleovenetian culture) and some model samples have been prepared by a modern artisan. The sample textures have been measured by X-ray Diffraction techniques. (111), (200) and (220) pole figures were used to calculate Orientation Distribution Functions and further recalculate pole figures and inverse pole figures. The results were compared with modern forging technology results. Textures are able to discern between hammering ancient techniques for sheet production and modern industrial rolling procedures. However, as it is demonstrated in the present work, forgery becomes difficult to detect if the goldsmith, properly warned, proceeds to erase the texture history with some hammering post-processing. The results of this contribution can offer to the archaeologists the opportunity to take into consideration the texture techniques in order to discuss the origin (culture) of the pieces and the characteristic mechanical process developed by the ancient artisan. Texture can also help the experts when discussing the originality of a certain piece keeping however in mind the cautions indicated in this publication.

Preferred crystallographic orientation in mature and juvenile wood

2007 ◽  
Vol 222 (3-4) ◽  
Author(s):  
Jan T. Bonarski ◽  
Wieslaw Olek
Keyword(s):  
Distribution Function ◽  
Juvenile Wood ◽  
Microfibril Angle ◽  
Orientation Distribution ◽  
Experimental Methods ◽  
X Ray Diffraction ◽  
Traditional Concept ◽  
X Ray ◽  
Pole Figures ◽  
The Mean

Investigations of the crystallograpically organized regions of mature and juvenile Scots pine wood were performed. Experimental methods of X-ray diffraction were applied. Incomplete pole figures were measured, in order to calculate the orientation distribution function. The differences in the texture of the mature and juvenile wood were determined. The traditional concept of the mean microfibril angle was enhanced by developing the misorientation parameters. Evident differences in the space arrangement of cellulose of the both zones of wood were identified and described.

scholarly journals Texture and Lamellae Distribution Functions in Lamellar Eutectics

1986 ◽  
Vol 6 (4) ◽  
pp. 265-287 ◽  
Author(s):  
H. J. Bunge
Keyword(s):  
Three Dimensional ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
X Rays ◽  
Two Dimensional ◽  
Absorption Factor ◽  
X Ray Diffraction ◽  
Diffraction Vector ◽  
X Ray ◽  
Pole Figures

The crystallographic orientation distribution and the geometrical lamellae orientation distribution in lamellar eutectics are, in general, not independent of each other. The combined orientation-lamellae distribution function depends on five angular parameters. X-ray diffraction in such eutectics may exhibit an anisotropic macroscopic absorption factor if the penetration depth of the X-rays is large compared with their planar size. As a consequence, the reflected X-ray intensity may depend on a third angle γ, i.e. a rotation of the sample about the diffraction vector s additionally to the usual pole figure angles α, β which describe the orientation of the diffraction vector s with respect to the sample coordinate system. It is thus necessary to measure three-dimensional generalized pole figures instead of conventional two-dimensional ones.

Analysis of Preferred Orientations in Linear Friction Welded (LFW) Aluminium Alloy Specimens using “One-shot” Multi-element Energy Dispersive Synchrotron X-ray Diffraction

2013 ◽  
Vol 28 (S2) ◽  
pp. S327-S332 ◽  
Author(s):  
M.Y. Xie ◽  
T.S. Jun ◽  
A.M. Korsunsky ◽  
M. Drakopoulos
Keyword(s):  
Powder Diffraction ◽  
Dissimilar Materials ◽  
Orientation Distribution ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
Matlab Toolbox ◽  
X Ray ◽  
Sample Rotation ◽  
Pole Figures ◽  
Linear Friction

Linear Friction Welding (LFW) has tremendous potential for joining components from similar and dissimilar materials, avoiding material melting and introducing minimal distortion and only moderate levels of residual stress. However, the significant amount of attendant shear introduces preferred crystal orientations that have not yet been well studied. The “one-shot” approach to the interpretation of multi-element energy-dispersive X-ray powder diffraction data allows preferred orientation analysis without any sample preparation (cutting or polishing) or sample rotation. The key step for texture analysis by X-ray powder diffraction is the derivation of the orientation distribution function (ODF) from experimental data. Matlab toolbox “MTEX” provides a powerful function “calcODF” based on the harmonics method for this purpose. In the study reported in this paper, energy dispersive X-ray diffraction patterns were collected using the “horseshoe” multi-element energy-dispersive Ge detector installed on the JEEP beamline at Diamond Light Source. A single exposure was used for each gauge volume of interest, and a line was scanned across an Aluminum 2024 alloy LFW sample. The patterns were converted into raw pole figures through single peak fitting and equal area projection. The ODF calculation was performed based on these pole figures using Matlab toolbox “MTEX”. As a result, full pole figures obtained after ODF calculation were obtained. These are presented and discussed. The results show that the thermal-mechanical processes that occur during the LFW process lead to significant modification of the orientation distribution, but cause only moderate changes in the texture index.

Determination of the wurtzite content and orientation distribution of nanowire ensembles

2009 ◽  
Vol 1206 ◽  
Author(s):  
Dominik Kriegner ◽  
Mario Keplinger ◽  
Julian Stangl ◽  
Aaron M. Andrews ◽  
Pavel Klang ◽  
...  
Keyword(s):  
Lattice Constant ◽  
Orientation Distribution ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pole Figures

AbstractWe present x-ray diffraction based methods to quantitatively determine the wurtzite content of nanowire ensembles and to investigate the effect of twinning. An increased lattice constant in growth direction is found for all investigated InAs and InP nanowire samples. This increase is independent of the wurtzite content. Using x-ray pole figures we find that twinning is present in GaAs/Si branched nanowires, which leads to 60° rotations of the lattice.

Effects of thermal modification on wood ultrastructure analyzed with crystallographic texture

Holzforschung ◽  
2014 ◽  
Vol 68 (6) ◽  
pp. 721-726 ◽  
Author(s):  
Wiesław Olek ◽  
Jan T. Bonarski
Keyword(s):  
Crystallographic Texture ◽  
Orientation Distribution ◽  
Crystalline Cellulose ◽  
Temporary Increase ◽  
X Ray Diffraction ◽  
X Ray ◽  
3D Texture ◽  
Lattice Symmetry ◽  
Pole Figures ◽  
Monoclinic Lattice

Abstract The changes in ultrastructure of thermally modified beech and poplar wood have been studied by means of the crystallographic texture analysis. The experimental pole figures have been registered based on the X-ray diffraction (XRD). The 3D texture function, i.e., the orientation distribution function (ODF) was calculated with the use of the procedure implemented for materials with the monoclinic lattice symmetry. The inverse pole figures were recalculated from the obtained ODF. Areas with specific crystallographic organization in wood were identified and gradual changes in intensities of moderately oriented areas were observed. Simultaneously, additional reorganization of crystalline cellulose was observed as a result of heat treatment. The integrated skeleton lines confirmed the gradual decomposition of hemicelluloses as well as the temporary increase of cellulose self-organization.

Analysis of orientation diagrams derived from a simulated quartz fabric

1987 ◽  
Vol 24 (3) ◽  
pp. 565-571
Author(s):  
John Starkey
Keyword(s):  
Direct Method ◽  
Simulated Data ◽  
Orientation Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fabric Analysis ◽  
Pole Figures ◽  
Multiplicity Factor ◽  
Number Of Faces ◽  
Quartz Fabric

A simulated quartz fabric is generated in which the c axes tend to be parallel to a single direction. A set of pole figures is computed corresponding to the pole figures that would be measured by X-ray fabric analysis. Comparisons are made between orientation diagrams derived from the "measured" pole figures both directly and via the orientation function. The derived pole figures and inverse pole figures and the crystal orientation matrix obtained by the direct method correlate more closely with the original, simulated data. The inverse pole figures derived from the orientation distribution function display spurious symmetry indicating nonexistent differences in equivalent specimen directions and in the orientation patterns of positive and negative crystallographic forms. It is demonstrated that the analysis and comparison of pole figures require that the number of faces belonging to the crystallographic forms represented in the pole figure must be taken into consideration. Further, where more than one form is present and the data are obtained by X-ray diffraction, the relative diffracting intensities must also be considered. This leads to the formulation of an effective multiplicity factor.

The measurement of orientation distribution and its application to quantitative X-ray diffraction analysis

Clay Minerals ◽  
1966 ◽  
Vol 6 (3) ◽  
pp. 127-142 ◽  
Author(s):  
R.M. Taylor ◽  
K. Norrish
Keyword(s):  
Particle Morphology ◽  
Orientation Distribution ◽  
Particle Orientation ◽  
Small Specimen ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naturally Occurring ◽  
Mathematical Relation ◽  
Degree Of Orientation ◽  
Orientation Distributions

AbstractUsing X-ray techniques, the orientation distributions of crystal planes in laboratory prepared and naturally occurring aggregates were measured. A small specimen was mounted on the axis of a goniometer and the diffracted intensity measured as the specimen was rotated. Mo radiation was used to reduce the absorption effects. A mathematical relation between the distribution of particles and the distribution of crystal planes was derived for platy and fibrous particles in flake-like and rod-shaped specimens.When diffracted intensities of the 001 reflection of several different kaolinites were corrected for the degree of orientation in the respective specimens, a constant value was obtained. This would enable quantitative diffraction analyses to be made without the large errors that can be introduced by orientation effects. The degree of particle orientation achieved appeared to be more dependent on particle morphology than on the method of sample preparation or formation.

X-Ray Diffraction Investigation of Electrochemically Deposited Copper

2004 ◽  
Vol 443-444 ◽  
pp. 201-204 ◽  
Author(s):  
Karen Pantleon ◽  
Jens Dahl Jensen ◽  
Marcel A.J. Somers
Keyword(s):  
Process Parameters ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pole Figures ◽  
Electrochemically Deposited ◽  
Cu Interconnect

Copper layers were deposited from acidic electrolytes containing different amounts of organic additives, designed for the formation of Cu-interconnect structures. Amorphous Ni-P substrates allow to study the unbiased growth of the electrodeposits. The crystallographic texture was investigated by the determination of X-ray diffraction (XRD) pole figures and the calculation of the orientation distribution functions. XRD results are discussed in relation to the morphologies of the electrodeposits as investigated with light optical microscopy and correlated with the process parameters during electrodeposition.

X-ray diffraction study of the degree of orientation

1964 ◽  
Vol 5 (1) ◽  
pp. 25-29 ◽  
Author(s):  
L.G. Kazaryan ◽  
D.Ya. Tsvankin
Keyword(s):  
Diffraction Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Degree Of Orientation
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