Here we describe how to visualize grain boundary properties, e.g., misorientation angle, misorientation axes. Therefore lets start by importing some EBSD data and reconstructing the grain structure.
The grain boundary segments of a list of grains are stored within the field
We may use the plot command to visualize the grain boundaries in the map
Accordingly, we can access the grain boundary of a specific grain by
For a multi-phase system, the location of specific phase transitions may be of interest. The following plot highlights all Forsterite to Enstatite phase transitions
Another type of boundaries is boundaries between measurements that belong to the same grain. This happens if a grain has a texture gradient that loops around these two measurements.
The boundary misorientation is the misorientation between the two neighboring pixels of a boundary segment. Depending of the misorientation angle one distinguishes between high angle and low angle grain boundaries. In MTEX we can visualize the boundary misorientation angle by the commands
The misorientation axes in crystal coordinates
Similarly as the rotational angle we may colorize the grain boundaries also according the misorientation axes. First of all we have to decide whether we want to visualize the rotational axis in crystal or coordinate system. Second we have to define a color key that translates rotational axes into colors.
Lets start with the rotational axes in crystal coordinates
As a colorbar replacement we plot the color key and on top of it the misorientation axes at the grain boundaries
The misorientation axes in specimen coordinates
Analyzing the misorientation axis in specimen coordinates is a bit more involved as it requires to extract the two neighboring orientations to each boundary segment. To do this we use the ebsdId stored in the boundary segments.
Full Misorientation Colorization
In order to visualize the full misorientation, i.e., axis and angle, one has to define a corresponding color key. One option is the color key described in the paper by S. Patala, J. K. Mason, and C. A. Schuh, Improved representations of misorientation information for grain boundary, Prog. Mater. Sci., vol. 57, no. 8, pp. 1383-1425, 2012.
Lets visualize the color key as axis angle sections through the misorientation space
Lets illustrate this color coding also at a iron sample.
At the end we plot the colorized misorientation space in axis angle sections. Note that in this plot misorientations mori and inv(mori) are associated.