how to determine volume fraction of different texture component from ODF maps

[Soupitak Pal]

Dear All, 

Could someone plz tell me that how should I calculate  volume fraction of different texture component from ODF maps generated from EBSD data. Please also suggest the necessary codes. Thanks in advance. 

- Soupitak 

[m.w...@sz.szmf.de]

Dear Soupitak,

if you have EBSD data it is, in my opinion, better to calculate the volume fractions directly:

[For MTEX 4.2.1]

ori = orientation('Euler',10*degree, 20*degree, 30*degree, CS,SS);

%number of all measurement points

all_points = numel(ebsd.x);

%EBSD subset with those points which orientations differ not more than 10° from

%ori

ori_EBSD = findByOrientation(ebsd,ori,10*degree);

%Volume fraction

Vol_ori_EBSD = numel(ori_EBSD.x)/all_points;

To calculate an ODF from the EBSD data and from this the volume fractions can lead to different results. Depending on your calculation parameters a smoothing of the texture will occur, especially for sharp textures.

I hope this helps.

Cheers,

Marco 

[Soupitak Pal]

Dear Marco, 

Thanks for your quick response. I wonder, how should I calculate volume fraction directly from the EBSD data. My sample is Fe-14Cr alloy, where the major texture components are alpha and gamma fibers. Even among the fibers there are different components exist like {001}<110> , {111}<112>, {111}<110> which  I can identify from the ODF map. I would like to quantitatively determine the volume fraction of respective texture components  originated after different processing conditions. If you kindly elaborate a bit more , it will be a great help. I am completely a newcomer in the MTEX world. 

Thanks 

Soupitak 

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[m.w...@sz.szmf.de]

Dear Soupitak,

no problem. To calculate the volume fractions of these components use:

 

ori = orientation('Miller',[1 0 0],[0 1 1],CS,SS)

to define the orientation and in the previous code. This checks how many EBSD measurement points have an orientation close to ori and then calculates their fraction.

 

If you are dealing with rolling textures than it may make sense to apply orthorhombic sample symmetry to get all equivalent orientations:

 

SS = specimenSymmetry('mmm')

Cheers,

Marco

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[D.H Lee]

Hi:

  It's very nice to see your answers for determine volume fraction of different texture component from ODF Maps. I still want to ask you some questions which I confused with for long time. Your answers will be a great help. My material has two phases, alpha-phase and beta-phase. I want to determine the texture components and the corresponding volume fraction of the materials. The codes I used like this:

        %compute the texture components and the corresponding volume fraction of alpha-phase

       ori = orientation('Euler',0*degree,0*degree,0*degree,CS.SS);

       ori 2= orientation('Euler',45*degree,0*degree,0*degree,CS.SS);

        all_points = numel(ebsd.x);
       ori_EBSD = findByOrientation(ebsd,ori,10*degree);

        ori2_EBSD = findByOrientation(ebsd,ori,10*degree);

       Vol_ori_EBSD = numel(ori_EBSD.x)/all_points;

       Vol_ori2_EBSD = numel(ori_EBSD.x)/all_points;

       

       %compute the texture components and the corresponding volume fraction of alpha-phase

       ori3 = orientation('Euler',35*degree,45*degree,0*degree,CS.SS);

        all_points = numel(ebsd.x);
       ori3_EBSD = findByOrientation(ebsd,ori,10*degree);

       Vol_ori3_EBSD = numel(ori_EBSD.x)/all_points;

             

    Is this right to compute the the texture components and the corresponding volume fraction of the materials containing alpha-phase and beta-phase?

 Cheers 

 D.L Lee

在 2016年9月30日星期五 UTC+8下午4:53:37，m.w...@sz.szmf.de写道：

[Marco Witte]

Hi,

 

if you calculate the texture components for two different phases you have to take into account their different crystal structures. So you should you use e.g. CS1 and CS2.

Also the orientations have to defined with the corresponding crystal symmetries.

If you would, for example, get a result like vol_ori_EBSD3= 0.3 and the fraction of this phase is 0.5, then 15 % of your measured area has an orientation close to ori3.

 

I hope this answers your question.  

 

With best regards
Marco