Pole figure Analysis from bulk XRD data

[Shaumik Lenka]

Hello,

I am working with cold draw steel wires and want to carry out pole figure, inverse pole figure, orientation density function analysis using MTex. I have the raw file for four reflection done using a XRD machine with file extension .xrdml. 

I have tried to plot the PF, IPFand ODF (phi2 =45) section using other proprietary software (Labotex) and want to compare the same using MTex. I am facing the following problems

[1] The PF, IPF and ODF (phi2=45) didn't match done through proprietary software and Mtex. I followed the following process to generate the PF, IPF and ODF

• Imported the raw pole figure in mtex with cs = m-3m (for ferrite of iron) and ss = mmm
• Calculated the ODF using the calcODF function.
• Plotted the recalculated PF and IPF using plotpdf and plotipdf functions respectively. 

[2]  Can i choose my way of contour levels for PF, IPF and ODF plotting in Mtex. If yes, then how to do ?

Please help me in this regard. Hope to hear from you. Hence obliged.

Regards

Shaumik Lenka

[Ralf Hielscher]

Hi Shaumik Lenka,

This aims to be a general answer to the question - I do not like the ODF I get from MTEX by reconstruction from pole figure data.

1. Please look at the raw pole figure data. Do you observe any meaningful texture? If not do not expect MTEX to find one.
2. Check you have set crystal symmetry and crystal axes length correctly.
3. Check background and defocussing correction was done correctly.
4. Check the reconstructed pole figure match the raw pole figures.
5. Even for very pronounced pole figures the reconstruction problem is very ill posed. This means that there are different ODFs repoducing the same pole figures. In general you can not expect to recover small details from pole figure to ODF reconstruction. Please rely only on the main features. Best is to use volume portions to describe the ODF / texture.

In your specific case your raw data look quite bad. I hardly see any structure in your data. Furthermore, defocusing correction seems to went wrong as you have extremely low values at 90 degree. For cubic symmetry this is impossible.

You can set the contour levels, e.g. to 1,2,3,4 by

plotPDF(odf,Miller(1,0,0),'contour',[1,2,3,4]

I hope this helps.

Ralf.