Electron Backscatter Diffraction In The Sem: Is Electron Diffraction In The Tem Obsolete?

1997 ◽  
Vol 3 (S2) ◽  
pp. 879-880
Author(s):  
J. R. Michael ◽  
M. E. Schlienger ◽  
R. P. Goehner

The technique of electron backscatter diffraction (EBSD) in the scanning electron microscope is currently finding a large number of important applications in materials science. The patterns formed through EBSD were first studied over 40 years ago. It has only been in the last 10 years that the technique has really begun to have an impact on the study of materials. The introduction of automatic pattern indexing software has enabled the technique to be used for mapping the orientation of a polycrystalline sample. The more exciting and universally interesting application of the technique has been the identification of micron and sub-micron sized crystalline phases based on their chemistry and crystallography determined by EBSD.EBSD is obtained by illuminating a highly tilted sample (>45° from horizontal) with a stationary electron beam. Electrons backscattered from the sample may satisfy the condition for channeling and will produce images that contain bands of increased and decreased intensity that are equivalent to electron channeling patterns.

1997 ◽  
Vol 3 (S2) ◽  
pp. 387-388 ◽  
Author(s):  
J. R. Michael

This tutorial will describe the technique of electron backscattered diffraction (EBSD) in the scanning electron microscope (SEM). To properly exploit EBSD in the SEM it is important to understand how these patterns are formed. This discussion will be followed by a description of the hardware required for the collection of electron backscatter patterns (EBSP). We will then discuss the methods used to extract the appropriate crystallographic information from the patterns for orientation determination and phase identification and how these operations can be automated. Following this, a number of applications of the technique for both orientation studies and phase identification will be discussed.EBSD in the SEM is a phenomenon that has been known for many years. EBSD in the SEM is a technique that permits the crystallography of sub-micron sized regions to be studied from a bulk specimen. These patterns were first observed over 40 years ago, before the development of the SEM and were recorded using a special chamber and photographic film.


2015 ◽  
Vol 48 (3) ◽  
pp. 776-785 ◽  
Author(s):  
Shirin Kaboli ◽  
Hendrix Demers ◽  
Nicolas Brodusch ◽  
Raynald Gauvin

The microstructure of a deformed Mg–Al–Ca alloy was imaged using an electron-beam energy of 20 keV in a cold field-emission scanning electron microscope. The backscattered electron (BSE) micrographs showed a non-uniform contrast, the simplest being in the form of parallel contours inside a number of grains. This contrast is described as rotation contour contrast (RCC) and is attributed to local rotation of the crystal during the deformation of the grain. A model is presented to relate the rotation of crystal planes about one rotation axis to the channeling contrast in the channeling pattern and, consequently, to RCC in the BSE micrograph. This model was validated with the electron backscatter diffraction technique such that the RCCs in the BSE micrograph were reconstructed using the electron backscatter diffraction pattern intensities. The appearance of the RCCs was attributed to the change in the electron-beam position across a Kikuchi band due to local crystal rotation.


2011 ◽  
Vol 702-703 ◽  
pp. 548-553 ◽  
Author(s):  
Stuart I. Wright ◽  
Jay A. Basinger ◽  
Matthew M. Nowell

Electron backscatter diffraction (EBSD) has become the preferred technique for characterizing the crystallographic orientation of individual grains in polycrystalline microstructures due to its ability to rapidly measure orientations at specific points in the microstructure at resolutions of approximately 20-50nm depending on the capabilities of the scanning electron microscope (SEM) and on the material being characterized. Various authors have studied the angular resolution of the orientations measured using automated EBSD. These studies have stated values ranging from approximately 0.1° to 2° [1-6]. Various factors influence the angular resolution achievable. The two primary factors are the accuracy of the detection of the bands in the EBSD patterns and the accuracy of the pattern center (PC) calibration. The band detection is commonly done using the Hough transform. The effect of varying the Hough transform parameters in order to optimize speed has been explored in a previous work [6]. The present work builds upon the earlier work but with the focus towards achieving the best angular resolution possible regardless of speed. This work first details the methodology used to characterize the angular precision then reports on various approaches to optimizing parameters to improve precision.


2015 ◽  
Vol 60 (3) ◽  
pp. 2267-2270 ◽  
Author(s):  
M.J. Szczerba

Abstract The self-accommodated non-modulated martensite of Ni-Mn-Ga single crystal was studied by transmission and scanning electron microscopy in the latter case using the electron backscatter diffraction technique. Three kinds of interfaces existing at different length scales were reported. The first, is the wavy and incoherent interface separating martensite variants observed on the micro-level with no-common crystallographic plane between them. The second is within a single martensite plate where the lattice rotates around one of the {110} pole to accommodate the interfacial curvature between martensite plates. Finally, at the nanoscale the third interface exists, a twin boundary separating internal nanotwins with the {112} type habit plane.


2011 ◽  
Vol 17 (3) ◽  
pp. 316-329 ◽  
Author(s):  
Stuart I. Wright ◽  
Matthew M. Nowell ◽  
David P. Field

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.


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