Phase Identification Using EBSD in the SEM: What Can be Done Today and What we Hope to do Tomorrow

1999 ◽  
Vol 5 (S2) ◽  
pp. 220-221
Author(s):  
J. R. Michael

Phase identification using electron backscatter diffraction (EBSD) in the SEM has become a useful and important tool for the characterization of crystalline materials. Phase identification is accomplished using EBSD in the following manner. First, a high quality camera must be added to the SEM. Suitable cameras use slow scan CCD imagers coupled either by a lens or a fiber optic bundle to a phosphor screen that is situated near the sample. A EBSD pattern is collected and EDS or WDS is used to determine qualitatively the chemistry of the area. An automated routine is then used to extract the positions and widths of the lines in the pattern followed by a calculation of the unit cell volume. This information coupled with the chemistry of the sample is then used to search a database of crystal structures. Currently, the ICDD's Powder Diffraction file of over 100,000 compounds is used. Once a list of potential matches is found the patterns are indexed and then simulated to demonstrate that the phase has been identified. This paper will demonstrate use of EBSD for phase identification and then will speculate on future developments.A particularly nice application of EBSD is the use of the technique for the identification of phases that form in welds. Figure 1a is an EBSD pattern obtained from a acicular phase in a superalloy weld. The phase was determined to be primarily Ti and Ni. Analysis of the patterns showed that the phase is Ni3Ti. Figure 1b shows the simulation for Ni3Ti overlaid on the experimental pattern demonstrating that the phase has been identified.

2014 ◽  
Vol 47 (4) ◽  
pp. 1466-1468 ◽  
Author(s):  
Lili Li ◽  
Sheng Ouyang ◽  
Yanqing Yang ◽  
Ming Han

Electron backscatter diffraction (EBSD) patterns provide a wealth of crystallographic information but disappointingly low accuracy. Adopting a strategy of compensating the poor accuracy by the large amount of information, a computer program, EBSDL, has been successfully developed to determine the unknown Bravais lattice of bulk crystalline materials using a single EBSD pattern. Unlike programs that perform phase identification, the new application is completely independent of chemical information.


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.


2013 ◽  
Vol 19 (S4) ◽  
pp. 103-104
Author(s):  
C.B. Garcia ◽  
E. Ariza ◽  
C.J. Tavares

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.


2000 ◽  
Vol 6 (S2) ◽  
pp. 954-955
Author(s):  
Steven R. Claves ◽  
Wojciech Z. Misiolek ◽  
William H. Van Geertruyden ◽  
David B. Williams

Electron Backscattering Diffraction (EBSD) is an important tool for analyzing the crystal grain orientation of a microstructure and can be used to formulate conclusions about microtexture, texture determined from individual grains. This technique has been used to study a 6xxx series aluminum alloy's response to the deformation of the extrusion process. Extrusion is the process by which a billet of material is forced, under high pressure, through a die. The material undergoes a significant decrease in cross sectional area, and is formed into a shape equivalent to the geometry of the die orifice. Different bearing lands are shown in shown in Figure 1. These surfaces form the part, and are designed to control the metal flow making it uniform through the die, thus yielding good mechanical properties. This research was focused on the resultant microstructure. The shaded regions of Figure 2 show the two surface regions where EBSD measurements were taken.


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.


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.


Sign in / Sign up

Export Citation Format

Share Document