Trying to match MTEX ipf map to OIM

[Ben Schuessler]

Hey All,

I am trying to get MTEX to plot IPF maps with the same color scheme as OIM.. It is really close except some odd coloring in some grains. (See attached)

I checked the Euler angles in the MTEX IPF map and they matched correctly with OIM, except they are different colors. I am not sure what is going wrong and where. Any help is much appreciated!

Below is the code used, however I also attached the .m file if needed.

Google Drive link for the .ang file used (~4Mb): https://drive.google.com/file/d/1R-cW8dFSj-ih-0ZSVVl_lN0VNFMYPJfO/view?usp=sharing

Thanks!

Ben

edit: Is this a side effect of the TSL colormap not being topological, which is why color jumps may occur?

 

close all

CS = {...
  'notIndexed',...
  crystalSymmetry('432', [3.6 3.6 3.6], 'mineral', 'Copper', 'color', [0.53 0.81 0.98])};

% plotting convention
plotx2north
plotzOutOfPlane

%% Import the Data

fname = 'FSW AL.ang'

% create an EBSD variable containing the data
ebsd = EBSD.load(fname,CS,'interface','ang',...
  'convertSpatial2EulerReferenceFrame','setting 2');

%% Plot IPF X Y Z

ipfkey = ipfTSLKey(ebsd)
ipfkey.inversePoleFigureDirection = xvector;
oriColors = ipfkey.orientation2color(ebsd.orientations);
plot(ebsd,oriColors)
hold on
% plot(grains.boundary,'linewidth',1)
title('IPF X')
hold off

nextAxis
hold on
ipfkey.inversePoleFigureDirection = yvector;
oriColors = ipfkey.orientation2color(ebsd.orientations);
plot(ebsd,oriColors)
% plot(grains.boundary,'linewidth',1)
title('IPF Y')
hold off

nextAxis
hold on
ipfkey.inversePoleFigureDirection = zvector;
oriColors = ipfkey.orientation2color(ebsd.orientations);
plot(ebsd,oriColors,'figSize','small')
% plot(grains.boundary,'linewidth',1)
title('IPF Z')
hold off
movegui('center')

% Plot TSL ipf key
figure
plot(ipfkey,'figSize','tiny')
movegui('center')

[Rüdiger Kilian]

Hi,
I guess your software is indexing the Laue group instead of 432. Have you tried using m-3m?

Cheers,
Rüdiger

[Ben Schuessler]

Hi Rüdiger,

Switching the symmetry to m-3m, did the trick! I overlooked that. Not sure why the software was using 432. 

Thanks,

Ben

[Gregory Sparks]

I had a similar issue with OIM-exported .ang files and the MTEX import wizard. It seems to be a bad interaction with how OIM defines the material symmetry in the exported text-format .ang file, and how MTEX reads and imports it. If you look into the .ang file, you will see the "Symmetry" definition for your material - in your case it is Al, in my case I was working with Ni and Ti. For Al and Ni, it is "43" in the .ang file. For Ti, it was "62". The MTEX import wizard reads those as aliases for the "432" and "622" enantiomorphic point groups, respectively. This is different from the correct "m-3m" and "6/mmm" symmetries for FCC and HCP metals (missing an inversion symmetry in both cases), and will cause the observed weird color jumps for certain orientations when using the TSL IPF colormap. 

This isn't really correctable in the MTEX import wizard - if it was changed to use "43" as an alias for the "m-3m" symmetry group, then something that actually had "432" symmetry might get imported wrong. It's easiest to just manually swap in the correct symmetry, as suggested here. There should probably be a note somewhere in the documentation that this happens ... it's not always an obvious issue.