Denoising of crystal orientation maps

2019 ◽  
Vol 52 (5) ◽  
pp. 984-996 ◽  
Author(s):  
R. Hielscher ◽  
C. B. Silbermann ◽  
E. Schmidl ◽  
Joern Ihlemann

This paper compares several well known sliding-window methods for denoising crystal orientation data with variational methods adapted from mathematical image analysis. The variational methods turn out to be much more powerful in terms of preserving low-angle grain boundaries and filling holes of non-indexed orientations. The effect of denoising on the determination of the kernel average misorientation and the geometrically necessary dislocation density is also discussed. Synthetic as well as experimental data are considered for this comparison. The examples demonstrate that variational denoising techniques are capable of significantly improving the accuracy of properties derived from electron backscatter diffraction maps.

2011 ◽  
Vol 44 (6) ◽  
pp. 1222-1226 ◽  
Author(s):  
Zongbin Li ◽  
Yudong Zhang ◽  
Claude Esling ◽  
Xiang Zhao ◽  
Liang Zuo

The microstructural and crystallographic characteristics of 5M martensite in an Ni50Mn28Ga22alloy were investigated by electron backscatter diffraction (EBSD) analysis. The microstructure of 5M martensite observed at room temperature can be characterized by broad plates with alternately distributed fine lamellae (variants). With the accurate EBSD orientation measurements and by application of monoclinic superstructure information, four twin-related variants in one broad plate were identified. On the basis of the correct orientation data of martensite variants acquired from the EBSD measurements, the more favourable orientation relationship between austenite and 5M martensite was revealed to be the Pitsch relation with (101)A//(1 {\overline 2} \hskip1{\overline 5})5Mand [10 {\overline 1}]A//[{\overline 5} \hskip1 {\overline 5} 1]5Mby detailed crystallographic calculation without residual austenite.


1999 ◽  
Vol 4 (2) ◽  
pp. 174-174
Author(s):  
Chen Xiaomei ◽  
Liu Jing ◽  
Wang Jianbo ◽  
Zhang Ruikang ◽  
Wang Dahai ◽  
...  

2009 ◽  
Vol 24 (3) ◽  
pp. 647-651 ◽  
Author(s):  
M. Rester ◽  
C. Motz ◽  
R. Pippan

Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) analyses of small indentations in copper single crystals exhibit only slight changes of the crystal orientation in the surroundings of the imprints. Far-reaching dislocations might be the reason for these small misorientation changes. Using EBSD and TEM technique, this work makes an attempt to visualize the far-propagating dislocations by introducing a twin boundary in the vicinity of small indentations. Because dislocations piled up at the twin boundary produce a misorientation gradient, the otherwise far-propagating dislocations can be detected.


2012 ◽  
Vol 18 (4) ◽  
pp. 876-884 ◽  
Author(s):  
Joseph R. Michael ◽  
Bonnie B. McKenzie ◽  
Donald F. Susan

AbstractUnderstanding the growth of whiskers or high aspect ratio features on substrates can be aided when the crystallography of the feature is known. This study has evaluated three methods that utilize electron backscatter diffraction (EBSD) for the determination of the crystallographic growth direction of an individual whisker. EBSD has traditionally been a technique applied to planar, polished samples, and thus the use of EBSD for out-of-surface features is somewhat more difficult and requires additional steps. One of the methods requires the whiskers to be removed from the substrate resulting in the loss of valuable physical growth relationships between the whisker and the substrate. The other two techniques do not suffer this disadvantage and provide the physical growth information as well as the crystallographic growth directions. The final choice of method depends on the information required. The accuracy and the advantages and disadvantages of each method are discussed.


2021 ◽  
Vol 54 (2) ◽  
pp. 513-522
Author(s):  
Edward L. Pang ◽  
Christopher A. Schuh

Accurately indexing pseudosymmetric materials has long proven challenging for electron backscatter diffraction. The recent emergence of intensity-based indexing approaches promises an enhanced ability to resolve pseudosymmetry compared with traditional Hough-based indexing approaches. However, little work has been done to understand the effects of sample position and orientation on the ability to resolve pseudosymmetry, especially for intensity-based indexing approaches. Thus, in this work the effects of crystal orientation and detector distance in a model tetragonal ZrO2 (c/a = 1.0185) material are quantitatively investigated. The orientations that are easiest and most difficult to correctly index are identified, the effect of detector distance on indexing confidence is characterized, and these trends are analyzed on the basis of the appearance of specific zone axes in the diffraction patterns. The findings also point to the clear benefit of shorter detector distances for resolving pseudosymmetry using intensity-based indexing approaches.


Symmetry ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 677
Author(s):  
Alexander Smirnov ◽  
Evgeniya Smirnova ◽  
Sergey Alexandrov

It is, in general, essential to investigate correlations between the microstructure and properties of materials. Plastic deformation often localizes within thin layers. As a result, many material properties within such layers are very different from the properties in bulk. The present paper proposes a new method for determining the thickness of a thin surface layer of intensive plastic deformation in metallic materials. For various types of materials, such layers are often generated near frictional interfaces. The method is based on data obtained by Electron Backscatter Diffraction. The results obtained are compared with those obtained by an alternative method based on microhardness measurements. The new method allows for determining the layer thickness of several microns in specimens after grinding. In contrast, the measurement of microhardness does not reveal the presence of this layer. The grain-based and kernel-based types of algorithms are also adopted for determining the thickness of the layer. Data processed by the strain contouring and kernel average misorientation algorithms are given to illustrate this method. It is shown that these algorithms do not clearly detect the boundary between the layer of intensive plastic deformation and the bulk. As a result, these algorithms are unable to determine the thickness of the layer with high accuracy.


2019 ◽  
Vol 196 ◽  
pp. 00057
Author(s):  
Evgeny Victorovich Boyko ◽  
Ilya Alexeevich Kostogrud ◽  
Dmitry Vladimirovich Smovzh ◽  
Pavel Evgenyevich Matochkin

The paper presents the technique of qualitative assessment of the strength of graphene layers adhesion to the surface of a copper substrate, where they are formed. The technique uses a complex of approved analytical methods: electron backscatter diffraction (EBSD), Raman spectroscopy and optical microscopy. The technique was tested on multilayer graphene grown on a copper grain with crystal orientation (111). The presented method can be used to assess the effectiveness of the methods of graphene transfer from grains with different crystal orientation.


2009 ◽  
Vol 42 (2) ◽  
pp. 234-241 ◽  
Author(s):  
David J. Dingley ◽  
Stuart I. Wright

Electron backscatter diffraction (EBSD) is a scanning electron microscope-based technique principally used for the determination and mapping of crystal orientation. This work describes an adaptation of the EBSD technique into a potential tool for crystal phase determination. The process can be distilled into three steps: (1) extracting a triclinic cell from a single EBSD pattern, (2) identifying the crystal symmetry from an examination of the triclinic cell, and (3) determining the lattice parameters. The triclinic cell is determined by finding the bands passing through two zone axes in the pattern including a band connecting the two. A three-dimensional triclinic unit cell is constructed based on the identified bands. The EBSD pattern is indexed in terms of the triclinic cell thus formed and the crystal orientation calculated. The pattern indexing results in independent multiple orientations due to the symmetry the crystal actually possesses. By examining the relationships between these multiple orientations, the crystal system is established. By comparing simulated Kikuchi bands with the pattern the lattice parameters can be determined. Details of the method are given for a test case of EBSD patterns obtained from the hexagonal phase of titanium.


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