Influence of Noise-Generating Factors on Cross-Correlation Electron Backscatter Diffraction (EBSD) Measurement of Geometrically Necessary Dislocations (GNDs)

2017 ◽  
Vol 23 (3) ◽  
pp. 460-471 ◽  
Author(s):  
Landon T. Hansen ◽  
Brian E. Jackson ◽  
David T. Fullwood ◽  
Stuart I. Wright ◽  
Marc De Graef ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Electron Backscatter Diffraction ◽  
Low Cost ◽  
Electron Backscatter ◽  
Deformation Mechanics ◽  
Ebsd Technique ◽  
Backscatter Diffraction ◽  
The Impact ◽  
Influence Of Noise ◽  
Shed Light

AbstractStudies of dislocation density evolution are fundamental to improved understanding in various areas of deformation mechanics. Recent advances in cross-correlation techniques, applied to electron backscatter diffraction (EBSD) data have particularly shed light on geometrically necessary dislocation (GND) behavior. However, the framework is relatively computationally expensive—patterns are typically saved from the EBSD scan and analyzed offline. A better understanding of the impact of EBSD pattern degradation, such as binning, compression, and various forms of noise, is vital to enable optimization of rapid and low-cost GND analysis. This paper tackles the problem by setting up a set of simulated patterns that mimic real patterns corresponding to a known GND field. The patterns are subsequently degraded in terms of resolution and noise, and the GND densities calculated from the degraded patterns using cross-correlation ESBD are compared with the known values. Some confirmation of validity of the computational degradation of patterns by considering real pattern degradation is also undertaken. The results demonstrate that the EBSD technique is not particularly sensitive to lower levels of binning and image compression, but the precision is sensitive to Poisson-type noise. Some insight is also gained concerning effects of mixed patterns at a grain boundary on measured GND content.

scholarly journals On the Use of EBSD and Microhardness to Study the Microstructure Properties of Tungsten Samples Prepared by Selective Laser Melting

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1215
Author(s):  
Mirza Atif Abbas ◽  
Yan Anru ◽  
Zhi Yong Wang
Keyword(s):  
Selective Laser Melting ◽  
Electron Backscatter Diffraction ◽  
Fusion Reactors ◽  
Laser Melting ◽  
Kikuchi Pattern ◽  
Plasma Facing Components ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Temperature Exposure ◽  
Backscatter Diffraction

Additively manufactured tungsten and its alloys have been widely used for plasma facing components (PFCs) in future nuclear fusion reactors. Under the fusion process, PFCs experience a high-temperature exposure, which will ultimately affect the microstructural features, keeping in mind the importance of microstructures. In this study, microhardness and electron backscatter diffraction (EBSD) techniques were used to study the specimens. Vickers hardness method was used to study tungsten under different parameters. EBSD technique was used to study the microstructure and Kikuchi pattern of samples under different orientations. We mainly focused on selective laser melting (SLM) parameters and the effects of these parameters on the results of different techniques used to study the behavior of samples.

Texture and Microstructure Evolution in Friction Stir Welded Cu-Al Sheets Characterized by EBSD

2011 ◽  
Vol 702-703 ◽  
pp. 574-577 ◽  
Author(s):  
Daniel Goran ◽  
G. Ji ◽  
M. N. Avettand-Fènoël ◽  
R. Taillard
Keyword(s):  
Microstructure Evolution ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Weld Interface ◽  
Friction Stir ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Texture and microstructure of FSW joined Al and Cu sheets were investigated by means of electron backscatter diffraction (EBSD) technique. The analysis has revealed a strong texture evolution on both sides of the weld interface as well as a very complex microstructure. Grains were found to be fully recrystallized on both sides of the weld and with different average diameters at different specific zones of the weld.

Heteroepitaxy of Ge on Cube-Textured Ni(001) Foils Through CaF2 Buffer Layer

MRS Advances ◽  
2016 ◽  
Vol 1 (43) ◽  
pp. 2947-2952
Author(s):  
L. Chen ◽  
Z.-H. Lu ◽  
T.-M. Lu ◽  
I. Bhat ◽  
S.B. Zhang ◽  
...  
Keyword(s):  
Buffer Layer ◽  
High Efficiency ◽  
Electron Backscatter Diffraction ◽  
Low Cost ◽  
High Quality ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Electron Backscatter ◽  
Image Position ◽  
Backscatter Diffraction

ABSTRACTEpitaxial Ge films are useful as a substrate for high-efficiency solar cell applications. It is possible to grow epitaxial Ge films on low cost, cube textured Ni(001) sheets using CaF2(001) as a buffer layer. Transmission electron microscopy (TEM) analysis indicates that the CaF2(001) lattice has a 45o in-plane rotation relative to the Ni(001) lattice. The in-plane epitaxy relationships are CaF2[110]//Ni[100] and CaF2[$\bar 1$10]//Ni[010]. Energy dispersive spectroscopy (EDS) shows a sharp interface between Ge/CaF2 as well as between CaF2/Ni. Electron backscatter diffraction (EBSD) shows that the Ge(001) film has a large grain size (∼50 μm) with small angle grain boundaries (< 8o). The epitaxial Ge thin film has the potential to be used as a substrate to grow high quality III-V and II-VI semiconductors for optoelectronic applications.

scholarly journals Application of Electron Backscatter Diffraction (EBSD) for Crystallographic Characterization of Aluminum-Doped Zinc Oxide Sputtered Films

2013 ◽  
Vol 19 (S4) ◽  
pp. 103-104
Author(s):  
C.B. Garcia ◽  
E. Ariza ◽  
C.J. Tavares
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Zinc Oxide ◽  
Electron Backscatter Diffraction ◽  
Wide Range ◽  
Electron Backscatter ◽  
Aluminum Doped Zinc Oxide ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Zinc Oxide is a wide band-gap compound semiconductor that has been used in optoelectronic and photovoltaic applications due to its good electrical and optical properties. Aluminium has been an efficient n-type dopant for ZnO to produce low resistivity films and high transparency to visible light. In addition, the improvement of these properties also depends on the morphology, crystalline structure and deposition parameters. In this work, ZnO:Al films were produced by d.c. pulsed magnetron sputtering deposition from a ZnO ceramic target (2.0 wt% Al2O3) on glass substrates, at a temperature of 250 ºC.The crystallographic orientation of aluminum doped zinc oxide (ZnO:Al) thin films has been studied by Electron Backscatter Diffraction (EBSD) technique. EBSD coupled with Scanning Electron Microscopy (SEM) is a powerful tool for the microstructural and crystallographic characterization of a wide range of materials.The investigation by EBSD technique of such films presents some challenges since this analysis requires a flat and smooth surface. This is a necessary condition to avoid any shadow effects during the experiments performed with high tilting conditions (70º). This is also essential to ensure a good control of the three dimensional projection of the crystalline axes on the geometrical references related to the sample.Crystalline texture is described by the inverse pole figure (IPF) maps (Figure 1). Through EBSD analysis it was observed that the external surface of the film presents a strong texture on the basal plane orientation (grains highlighted in red colour). Furthermore it was possible to verify that the grain size strongly depends on the deposition time (Figure 1 (a) and (b)). The electrical and optical film properties improve with increasing of the grain size, which can be mainly, attributed to the decrease in scattering grain boundaries which leads to an increasing in carrier mobility (Figure 2).The authors kindly acknowledge the financial support from the Portuguese Foundation for Science and Technology (FCT) scientific program for the National Network of Electron Microscopy (RNME) EDE/1511/RME/2005.

Twin and topotactic growth of β-eucryptite dendrites and their lattice coincidence analysed by the reticular theory

2013 ◽  
Vol 46 (1) ◽  
pp. 216-223
Author(s):  
Shan-Rong Zhao ◽  
Hai-Jun Xu ◽  
Rong Liu ◽  
Qin-Yan Wang ◽  
Xian-Yu Liu
Keyword(s):  
Solid Solution ◽  
Crystallographic Orientation ◽  
Electron Backscatter Diffraction ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction ◽  
Orientation Determination

Snowflake-shaped dendrites of β-eucryptite–β-quartz solid solution were artificially crystallized in a matt glaze, and the crystallographic orientation of the dendrites was analysed by the electron backscatter diffraction (EBSD) technique. The six branches of a snowflake-shaped dendrite in the plane (0001) are along 〈110〉. From the orientation determination, a twin relationship and a topotactic relationship between dendrites were found. The twin axes are [011], [0{\overline 1}1] and [210], and the twin planes perpendicular to the twin axes are ({\overline 1}2{\overline 1}2) and (1{\overline 2}12). From the reticular theory of twinning, it was calculated that the twin indexn= 2 and the obliquity ω = 3.2877°. The studied dendrite is a twin by reticular pseudomerohedry with low twin index and obliquity. In the topotactic growth, no twin elements have been found, but the three main crystallographic directions 〈001〉, 〈210〉 and 〈110〉 of the two dendritic crystals overlap each other. The degree of lattice coincidence between the two crystals in this topotactic growth is also discussed.

A Review of Strain Analysis Using Electron Backscatter Diffraction

2011 ◽  
Vol 17 (3) ◽  
pp. 316-329 ◽  
Author(s):  
Stuart I. Wright ◽  
Matthew M. Nowell ◽  
David P. Field
Keyword(s):  
Plastic Strain ◽  
Materials Science ◽  
Electron Backscatter Diffraction ◽  
Strain Analysis ◽  
Current State ◽  
Mapping Parameters ◽  
Submicron Scale ◽  
Electron Backscatter ◽  
Ebsd Technique ◽  
Backscatter Diffraction

AbstractSince the automation of the electron backscatter diffraction (EBSD) technique, EBSD systems have become commonplace in microscopy facilities within materials science and geology research laboratories around the world. The acceptance of the technique is primarily due to the capability of EBSD to aid the research scientist in understanding the crystallographic aspects of microstructure. There has been considerable interest in using EBSD to quantify strain at the submicron scale. To apply EBSD to the characterization of strain, it is important to understand what is practically possible and the underlying assumptions and limitations. This work reviews the current state of technology in terms of strain analysis using EBSD. First, the effects of both elastic and plastic strain on individual EBSD patterns will be considered. Second, the use of EBSD maps for characterizing plastic strain will be explored. Both the potential of the technique and its limitations will be discussed along with the sensitivity of various calculation and mapping parameters.

scholarly journals Polarity Determination in EBSD Patterns Using the Hough Transformation

2021 ◽  
pp. 1-11
Author(s):  
Tilman Zscheckel ◽  
Wolfgang Wisniewski ◽  
Christian Rüssel
Keyword(s):  
Atomic Number ◽  
Electron Backscatter Diffraction ◽  
Lattice Plane ◽  
Hough Transformation ◽  
Automated Evaluation ◽  
Electron Backscatter ◽  
Polarity Determination ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Currently, the automated electron backscatter diffraction (EBSD) technique only allows the differentiation of the Laue groups based on an electron backscatter pattern (EBSP). This article shows that information concerning the lattice plane polarity is not only stored in the EBSP, but also in the Hough transformed EBSP where it can be easily accessed for automated evaluation. Polar Kikuchi bands lead to asymmetric peaks during the Hough transformation that are dependent on the atomic number difference of the involved atoms. The effect can be strong enough to be detected when evaluating the intensities of the regular excess and deficiency lines. Polarity detection from the Hough transformation of an EBSP cannot only enhance the utility of the EBSD technique and expand the information gained from it, but also illustrates a path toward automated polarity determination during EBSD scans.

Resolving pseudosymmetry in γ-TiAl using cross-correlation electron backscatter diffraction with dynamically simulated reference patterns

2018 ◽  
Vol 51 (3) ◽  
pp. 655-669 ◽  
Author(s):  
Brian Jackson ◽  
David Fullwood ◽  
Jordan Christensen ◽  
Stuart Wright
Keyword(s):  
Cross Correlation ◽  
Electron Backscatter Diffraction ◽  
Experimental Sample ◽  
Correct Orientation ◽  
Pattern Noise ◽  
Electron Backscatter ◽  
Diffraction Patterns ◽  
Backscatter Diffraction ◽  
Pattern Resolution ◽  
Pattern Center

Pseudosymmetry is a phenomenon that occurs when grains with different lattice parameters produce nearly identical diffraction patterns such that conventional electron backscatter diffraction (EBSD) techniques are unable to unambiguously differentiate the lattice orientations. This commonly occurs in materials with near-unity tetragonality, such as γ-TiAl. The current study uses cross-correlation EBSD to resolve pseudosymmetry in γ-TiAl. Three dynamically simulated reference patterns are generated for each point in the scan, one for each of the three potential pseudosymmetric orientations, which are subsequently correlated with the original pattern using six different methods in order to identify the correct orientation. The methods are first applied to a scan of dynamically simulated patterns, which is used to evaluate the sensitivity of the method to pattern resolution, pattern noise and pattern center error. It was determined that all six methods were 100% successful up to about 13 µm of pattern center error and pattern resolutions of about 80 × 80 pixels, and hence the methods were applied to an experimental sample of lamellar γ-TiAl. A hybrid combination of two of the methods was shown to successfully select the correct pseudosymmetry for about 96% of the points in the scan, improving upon the 70% accuracy of the Hough-based methods for the current study and 90% accuracy for previous studies resolving pseudosymmetry in lamellar γ-TiAl.

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