would you mind to attach ur raw data?

Hi, Maykel, I attach 3 files (xrd-1, xrd-2, standard W-H-plot (the first figure is for xrd-1, the second fiture is for xrd-2)).

The following six planes were used to plot the W-H figure: (10-10), (10-11), (11-20), (20-20), (11-22) and (20-21).

Would you please have a check for me? Thank you very much.

Hi Gaoming,

I see you data showing some scattered points in FHWM along the linear fit.

Which means that this material is not showing isotropic properties in size or micro-strain as well in principle. If your sample is like a sphere, and no micro-strains(defects), then your FWHM would be followed by Caglioti eq which is describing that FWHMs are exhibiting square equation as a function of 2 theta. So, I am expecting there are some anisotropic broadening resulting in FWHM variation. So, you need to check all (hkl) of the bragg peaks and match them with FWHM values.

After that, you can calculate individual W-H plot by selecting same or similar planes.

Our s/w, Highscore plus, is providing TCH+Stephene model on fitting FWHMs. Which is useful for estimate how your crystallite looks like by seeing strain distribution in 3-dimension.

Your sample looks similar to highly textured hexagonal Mg. Probably the measurement was done with lambda about 70 pm. Without knowing the instrumental broadening it is difficult to determine the microstructure. But the peaks indexed (hk0) seem to be less broadened than the peaks indexed (hkl) (l>0). This may be caused by crystallites showing an anisotropic crystallite size (as Daniel suggested), more exactly a  smaller crystallite size in (001) direction than in (100) direction. But also stacking faults will produce a similar anisotropic line width even in the case of isotropic crystallite size. But without knowing the instrumental broadening it is hard to distinguish.

Yes, your sample is highly textured, has anisotropy size-strain broadening and lattice strains due to axial stress as what i got with MAUD. Try to fit 00l and hk0 planes separately or analyze your data using WPPM* which can give you the dislocation density.

*M. Leoni, T. Confente & P. Scardi, “PM2K: a flexible program implementing Whole Powder Pattern Modelling”, Z. Kristallogr. Suppl. 23 (2006) 249-254. Contacts: [email protected] or [email protected]

Thank you very much for all suggestions.

My sample is hot rolled magnesium, has very strong basal texture. I have removed the instrumental broadening for the W-H figure. (hk0) and (hkl) are different may be because of the texture, but in my results, there are only 6 peaks in the axis direction. If I fit (hk0) and (hkl) planes separately, the peaks will be not enough to fit accurately.

I want to find to find a parameter C to modify the g for every planes to promote the fitting quality.

Gaoming Zhu

Whether to use the W-H plot or the modified W-H plot, it totally depends on the sample synthesis and post-synthesis procedures. In this video, I have discussed the three models i.e. Uniform Deformation Model (UDM), Uniform Stress Deformation Model (USDM), and Uniform Deformation Energy Density Model (UDEDM). Crystallite size, microstrain and energy density have been calculated under these models. I have provided the practice file (Origin file) as well as the calculation file (Excel file) in the video description. Thanks

https://www.youtube.com/watch?v=OG-G6V9X8l0

最好的办法还是精修