EBSD vs. MTEX Pole Figures

[Omar Al-Abri]

Dear All,

I performed EBSD Analysis of steel sample (Iron-alpha) and obtained the texture given in the attached BCC.txt file. I used the Euler angles from the EBSD to plot the pole figures using MTEX. However, comparing the pole figures obtained from EBSD with the ones from MTEX shows a difference in the distribution as shown in the figures given below. 

I used the following code to plot the pole figures in mtex:

close all

clear all

clc

% crystal symmetry

CS = crystalSymmetry('m-3m', [2.8665 2.8665 2.8665], 'mineral', 'Iron-alpha', 'color', 'light blue');

% specimen symmetry

SS = specimenSymmetry('1');

% plotting convention

setMTEXpref('xAxisDirection','east');

setMTEXpref('zAxisDirection','outOfPlane');

%% Specify File Names

% path to files

pname = 'C:\Users\user\Desktop\Texture';

% which files to be imported

fname = [pname '\BCC.txt'];

%% Import the Data

% create a variable containing the orientation data from EBSD

CPFEM = load(fname);

% define euler angles

ori = orientation('Euler',CPFEM(:,1)*degree,CPFEM(:,2)*degree,CPFEM(:,3)*degree,CS,'Bunge');

%% Plot orientations

figure;

plotPDF(ori,[Miller(1,0,0,CS),Miller(1,1,0,CS),Miller(1,1,1,CS)],'all','contourf','grid');

mtexColorbar;

CLim(gcm,[0.09 3.79]);

The Pole figure from EBSD is:

The Pole figure form MTEX is:

As per CHANNEL 5 software manual, the Euler angles from EBSD are given in Bunge convention. 

Looking forward to your advice.

Regards,

Omar

  

[Rüdiger Kilian]

Hi Omar,
it looks like your channel5 derived polefigure comes from  125000 points while your text file contains only ~7500 points. Could it be that you are comparing an area-weighted pole figure (channel5, taking every measurement point in to account) with something like  one-orientation-per grain data (your .txt file)?
Cheers,
Rüdiger

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From: mtex...@googlegroups.com [mtex...@googlegroups.com] on behalf of Omar Al-Abri [omar...@hotmail.com]
Sent: Sunday, November 08, 2015 6:11 PM
To: MTEX
Subject: {MTEX} EBSD vs. MTEX Pole Figures

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[Omar Al-Abri]

 

Hi Rudiger,

Thanks for your reply.

First of all, there was a mistake in the BCC.txt file. The correct one for the above MTEX pole figure is attached now. 

Regarding the texture obtained from EBSD, there was no information in the exported file that shows the weight of the texture. So, I believe that every orientation is represented by the Euler angles given in the BCC.txt.

I tested another case and the same observation is obtained:

The texture information of the above pole figures is the one attached in the original message 

Regards,

Omar

 

 

[Omar Al-Abri]

Dear Ralf,

Would you pleases assist with this case!

Further to the explanation given above along with the comment from Rudiger regarding the data points used in the EBSD pole figure, I re-plotted the pole figure again from the Channel 5 software and I used single point for each grain indexed (7446 points) in the EBSD. Based on that, I got the following results, which are still different from the MTEX. I tried to rotate the pole figure from MTEX to match it with the EBSD but without success! Texture data obtained from EBSD are attached.

Looking forward to your advice

Omar

[ruediger Kilian]

Hi Omar,
also, are you sure that

% plotting convention
setMTEXpref('xAxisDirection','east');
setMTEXpref('zAxisDirection','outOfPlane’);

is the correct one for you, or respectively, you might have set a different coordinate system option in channel5 when exporting to .txt. Y0 and X0 is not necessarily the same as x,y in mtex.
Cheers,
Rüdiger

> The Pole figure form MTEX is:
>
>
>
>
>

> As per CHANNEL 5 software manual, the Euler angles from EBSD are given in Bunge convention.
>
> Looking forward to your advice.
>
> Regards,
>
> Omar
>
>
>

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> <BCC.txt>

[Omar Al-Abri]

Hi Rudiger,

Thanks for your response and suggestions. It was exactly as you mentioned. I changed the coordinate system option in channel5 and I got exactly like MTEX.

Thanks again and best regards,

Omar