Short EBSD Analysis Tutorial

How to detect grains in EBSD data and estimate an ODF.

Data import

EBSD data may be imported by the import_wizard by typing

import_wizard

or by the command

fileName = [mtexDataPath filesep 'EBSD' filesep 'Forsterite.ctf'];
ebsd = loadEBSD(fileName)
Warning: .ctf files have usualy
inconsistent conventions for spatial
coordinates and Euler angles. You may
want to use one of the options
'convertSpatial2EulerReferenceFrame' or
'convertEuler2SpatialReferenceFrame' to
correct for this 
 
ebsd = EBSD  
 
 Phase  Orientations     Mineral        Color  Symmetry  Crystal reference frame
     0   58485 (24%)  notIndexed                                                
     1  152345 (62%)  Forsterite   light blue       mmm                         
     2   26058 (11%)   Enstatite  light green       mmm                         
     3   9064 (3.7%)    Diopside    light red     12/m1        X||a*, Y||b, Z||c
 
 Properties: bands, bc, bs, error, mad, x, y
 Scan unit : um
 

A quick overview of the phases within your data set gives the plot

plot(ebsd)

MTEX supports a wide variety of EBSD file formats. Recommended are text- base file formats like .ang and .ctf over binary file formats like .osc. Special attention has to be paid to the alignment of sample reference frame X Y Z. Different vendors use different conventions. Even the reference frame for the Euler angles and for the spatial coordinates do not need to coincide. How to deal with this is discussed in a separate section.

Visualize EBSD data

The alignment of the Euler reference frame can be verified by plotting pole figures and comparing them with the pole figures of the vendors system.

% we first need to extract the crystal symmetry of Forsterite
csForsterite = ebsd('Forsterite').CS

% this plots the (001) pole figure of the Forsterite phase
plotPDF(ebsd('Forsterite').orientations,Miller(0,0,1,csForsterite))

% display Euler angle reference frame X, Y, Z
text([vector3d.X,vector3d.Y,vector3d.Z],{'X','Y','Z'},'backgroundColor','w')
 
csForsterite = crystalSymmetry  
 
  mineral : Forsterite
  color   : light blue
  symmetry: mmm       
  a, b, c : 4.8, 10, 6
 
  I'm plotting 1250 random orientations out of 152345 given orientations
  You can specify the the number points by the option "points".
  The option "all" ensures that all data are plotted
plot(ebsd('Forsterite'),ebsd('Forsterite').orientations,'coordinates','on')