Electron Backscatter Diffraction Data (The Class EBSD)

Class Description

The following mindmap might give a basic idea about EBSD data analyis in MTEX, with the ability of grain modelling for spatial data. It offers various way of interpreting individual orientation measurements, i.e. in terms of quantifying macro-,micro- and mesotexture.

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Import of EBSD Data

The most comfortable way to import EBSD data into MTEX is to use the import wizard, which can be started by the command

import_wizard('ebsd')

If the dataset is in a format supported by MTEX, the import wizard generates a script which imports the data. More information about the import wizard and a list of supported file formats can be found ImportEBSDData.html,here. A typical script generated by the import wizard looks a follows.

cs = crystalSymmetry('m-3m','mineral','Fe');      % crystal symmetry

% file names
fname = fullfile(mtexDataPath,'EBSD','85_829grad_07_09_06.txt');

% load data
ebsd = EBSD.load(fname,'CS',cs,...
  'Bunge','ignorePhase',[0 2],...
  'ColumnNames', { 'Phase' 'x' 'y' 'Euler 1' 'Euler 2' 'Euler 3'},...
  'Columns', [2 3 4 5 6 7])

 
ebsd = EBSD  
 
 Phase  Orientations  Mineral       Color  Symmetry  Crystal reference frame
     1  48184 (100%)       Fe  light blue      m-3m                         
 
 Properties: x, y
 Scan unit : um
 

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Plotting EBSD Data

EBSD data are plotted using the command EBSD.plot.html,plot. It assigns a color to each orientation and plots a map of these colors. There are several options to specify the way the colors are assigned.

ipfKey = ipfColorKey(ebsd);
plot(ebsd,ipfKey.orientation2color(ebsd.orientations))

In order to understand the color coding, one can plot the coloring of the corresponding inverse pole figure via

plot(ipfKey)
hold on
plotIPDF(ebsd('Fe').orientations,xvector,'markerSize',3,'points',500,'marker','o','markerfacecolor','none','markeredgecolor','k')
hold off

  I'm plotting 500 random orientations out of 48184 given orientations

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Modify EBSD Data

MTEX offers a lot of operations to analyze and manipulate EBSD data, e.g.

An exhaustive introduction how to analyze and modify EBSD data can be found here

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Calculate an ODF from EBSD Data

The command calcODF performs an ODF calculation from EBSD data using kernel density estimation EBSD data. For a precise explanation of the algorithm and the available options please look at here.

odf = calcODF(ebsd('Fe').orientations,'halfwidth',10*degree)
plotPDF(odf,Miller(1,0,0,odf.CS),'antipodal')

 
odf = ODF  
  crystal symmetry : Fe (m-3m)
  specimen symmetry: 1
 
  Harmonic portion:
    degree: 25
    weight: 1
 

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Simulate EBSD Data

Simulating EBSD data from a given ODF is useful to analyze the stability of the ODF estimation process. There is an example demonstrating how to determine the number of individual orientation measurements to estimate the ODF up to a given error. The MTEX command to simulate EBSD data is calcEBSD, e.g.

ori = calcOrientations(unimodalODF(orientation.id(cs)),500)
plotPDF(ori,Miller(1,0,0,cs),'antipodal','MarkerSize',3)

 
ori = orientation  
  size: 500 x 1
  crystal symmetry : Fe (m-3m)
  specimen symmetry: 1
 
  I'm plotting 208 random orientations out of 500 given orientations
  You can specify the the number points by the option "points".
  The option "all" ensures that all data are plotted

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Demo

For a more exhaustive description of the EBSD class have a look at the EBSD demo!

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Complete Function list

*EBSD* is the low level constructor for an *EBSD* object representing EBSD
data. For importing real world data you might want to use the predefined
<ImportEBSDData.html EBSD interfaces>. You can also simulate EBSD data
from an ODF by the command <ODF.calcEBSD.html calcEBSD>.
Syntax
ebsd = EBSD(rotations,phases,CSList)
Input
orientations	@orientation
CS	crystal / specimen @symmetry
Options
phase	specifing the phase of the EBSD object
options	struct with fields holding properties for each orientation
xy	spatial coordinates n x 2, where n is the number of input orientations
unitCell	for internal use
See also
ODF/calcEBSD EBSD/calcODF EBSD/load

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