scholarly journals Investigating crystal orientation patterns of foraminiferal tests by electron backscatter diffraction analysis

2020 ◽  
Vol 32 (6) ◽  
pp. 613-622
Author(s):  
Stephanie Pabich ◽  
Christian Vollmer ◽  
Nikolaus Gussone
Keyword(s):  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Spot Size ◽  
Geochemical Data ◽  
Test Surface ◽  
Time Resolved ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Over Time ◽  
Foraminiferal Test

Abstract. We studied the crystallographic orientation of calcite crystals in benthic foraminifers by electron backscatter diffraction (EBSD). Individuals of two species, Gyroidinoides soldanii and Cibicidoides grimsdalei, featuring different test structures, were investigated for a time span covering 43 Myr. The aims of this study are to visualize test structure differences in foraminifers and to reveal potential changes in crystal orientation and grain size over time caused by diagenetic reactions such as recrystallization. Such recrystallization effects over time may aid in the interpretation of time-resolved geochemical data obtained on foraminiferal samples for paleo-environmental reconstructions. The EBSD patterns clearly resolve the different test structures of the two species. Cibicidoides grimsdalei has the c axes perpendicular to the test surface. An apparent shift in the preferred crystal orientation can most likely be attributed to a mismatch between the equatorial plane and cutting plane of the foraminiferal test, highlighting the importance of reproducible preparation techniques. In Gyroidinoides soldanii, the c axes of the calcite crystals show a broader distribution of the crystals with no preferred orientation. The specimens show no change in crystal sizes over time, with a frequency maximum corresponding to the spot size of the electron beam. Overall, the differences between the two species demonstrate that EBSD is a powerful tool to visualize and differentiate between foraminiferal test structures.

Where are the geometrically necessary dislocations accommodating small imprints?

2009 ◽  
Vol 24 (3) ◽  
pp. 647-651 ◽  
Author(s):  
M. Rester ◽  
C. Motz ◽  
R. Pippan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Twin Boundary ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Transmission Electron ◽  
Electron Backscatter ◽  
Copper Single Crystals ◽  
Backscatter Diffraction ◽  
Small Misorientation

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.

scholarly journals Crystal orientation and detector distance effects on resolving pseudosymmetry by electron backscatter diffraction

2021 ◽  
Vol 54 (2) ◽  
pp. 513-522
Author(s):  
Edward L. Pang ◽  
Christopher A. Schuh
Keyword(s):  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Detector Distance ◽  
Recent Emergence ◽  
Distance Effects ◽  
Electron Backscatter ◽  
Sample Position ◽  
Position And Orientation ◽  
Diffraction Patterns ◽  
Backscatter Diffraction

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.

scholarly journals Method for determining the adhesion force between graphene and copper

2019 ◽  
Vol 196 ◽  
pp. 00057
Author(s):  
Evgeny Victorovich Boyko ◽  
Ilya Alexeevich Kostogrud ◽  
Dmitry Vladimirovich Smovzh ◽  
Pavel Evgenyevich Matochkin
Keyword(s):  
Crystal Orientation ◽  
Adhesion Force ◽  
Electron Backscatter Diffraction ◽  
Copper Substrate ◽  
Qualitative Assessment ◽  
Multilayer Graphene ◽  
Graphene Layers ◽  
Electron Backscatter ◽  
Graphene Transfer ◽  
Backscatter Diffraction

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.

Determination of crystal phase from an electron backscatter diffraction pattern

2009 ◽  
Vol 42 (2) ◽  
pp. 234-241 ◽  
Author(s):  
David J. Dingley ◽  
Stuart I. Wright
Keyword(s):  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Hexagonal Phase ◽  
Three Dimensional ◽  
Lattice Parameters ◽  
Crystal Phase ◽  
Test Case ◽  
Electron Backscatter ◽  
Ebsd Pattern ◽  
Backscatter Diffraction

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.

Macroscopic Yield Function Predicted by Crystal Plasticity Simulation on Ultrafine-Grained Aluminum

2016 ◽  
Vol 725 ◽  
pp. 249-254 ◽  
Author(s):  
Yoshiteru Aoyagi
Keyword(s):  
Crystal Plasticity ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Biaxial Tension ◽  
Yield Function ◽  
Roll Bonding ◽  
Ultrafine Grained ◽  
Electron Backscatter ◽  
Dislocation Sources ◽  
Backscatter Diffraction

In this study, using experiment results obtained by electron backscatter diffraction, information on crystal orientation is introduced into a computational model for crystal plasticity simulation considering the effects of grain boundaries and dislocation sources to express the effect of the microstructure of ultrafine-grained metals. Finite-element simulations are performed for a polycrystal of an aluminum plate under biaxial tension. The multiscale crystal plasticity simulations depict the yield surface of the ultrafine-grained aluminum produced by accumulative roll-bonding processes. The anisotropic material coefficients of a higher-ordered yield function for ultrafine-grained aluminum are derived using a genetic algorithm.

Denoising of crystal orientation maps

2019 ◽  
Vol 52 (5) ◽  
pp. 984-996 ◽  
Author(s):  
R. Hielscher ◽  
C. B. Silbermann ◽  
E. Schmidl ◽  
Joern Ihlemann
Keyword(s):  
Variational Methods ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Sliding Window ◽  
Orientation Data ◽  
Kernel Average Misorientation ◽  
Orientation Maps ◽  
Electron Backscatter ◽  
Backscatter Diffraction

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.

scholarly journals Analysis Of Surface Orange Peel Of Automotive Aluminum Alloy Pipe Using Electron Backscatter Diffraction (EBSD)

2016 ◽  
Vol 1 (1) ◽  
pp. 24 ◽  
Author(s):  
D.Y. Chao ◽  
W.Z. Shao ◽  
J.T. Jiang ◽  
L. Zhen
Keyword(s):  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Tube Hydroforming ◽  
Orange Peel ◽  
Automotive Application ◽  
Electron Backscatter ◽  
Out Of Plane ◽  
Grain Orientations ◽  
Plane Displacement ◽  
Backscatter Diffraction

<p>The occurrence of orange peel in 6xxx alloy tube for automotive application was studied by super depth metallographic microscope and EBSD. The results revealed obvious ups and downs morphology at the surface after tube hydroforming. Compared with the undeformed case, more grains existed in the concave areas rather than individual out-of-plane displacement. The influence of surface orange peel on grain boundary morphology, crystal orientation, and texture are discussed. It is concluded, that surface orange peel is controlled by the spatial distribution of grain orientations and grain size through the thickness of the sample.</p>

scholarly journals Twin domain imaging in topological insulator Bi2Te3 and Bi2Se3 epitaxial thin films by scanning X-ray nanobeam microscopy and electron backscatter diffraction

2017 ◽  
Vol 50 (2) ◽  
pp. 369-377 ◽  
Author(s):  
Dominik Kriegner ◽  
Petr Harcuba ◽  
Jozef Veselý ◽  
Andreas Lesnik ◽  
Guenther Bauer ◽  
...  
Keyword(s):  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Domain Size ◽  
Epitaxial Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Twin Domain ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Diffraction Microscopy

The twin distribution in topological insulators Bi2Te3 and Bi2Se3 was imaged by electron backscatter diffraction (EBSD) and scanning X-ray diffraction microscopy (SXRM). The crystal orientation at the surface, determined by EBSD, is correlated with the surface topography, which shows triangular pyramidal features with edges oriented in two different orientations rotated in the surface plane by 60°. The bulk crystal orientation is mapped out using SXRM by measuring the diffracted X-ray intensity of an asymmetric Bragg peak using a nano-focused X-ray beam scanned over the sample. By comparing bulk- and surface-sensitive measurements of the same area, buried twin domains not visible on the surface are identified. The lateral twin domain size is found to increase with the film thickness.

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