Dear Sina, before u go into that calculation u need to improve ur data quality. As shown in the attached picture ur max intensity is less than 500 cts.

Ur sample is powder or bulk? what is the step scan and scan time?

It can be calculate by PM2K; the software that implement WPPM as mention by Eduard.

To do so u need high quality data and SRM scan to get the instrument broadening.

U cud contact Prof Matteo Leoni for the free software (Maybe the FPA already implemented in the software but this also need the details of inst. setting)

I don't think you can do this with XRD, but maybe someone will correct me. I thought you had to etch and count the dislocation lines under microscopy.

 I'm very interested :-)

https://www.researchgate.net/post/How_do_I_compute_b_Burgers_Vector_correctly_using_the_Hirsch_approach_to_computing_dislocation_density_employing_XRD_rocking_curve_profile_analysis?_tpcectx=profile_questions

Well done, Ravi.  I know there is strain broadening for peaks in XRD (which can be a confusion if you want crystallite size via the Scherrer equation).  Somehow strain and dislocation will be related (at least in my one remaining neuron - on time share at present) - so one thinks intuitively that there should be a route to this via XRD.

"I thought you had to etch and count the dislocation lines under microscopy." So do many others including myself :-)

Here are some of the challenges with that approach:

"I don't think you can do this with XRD". As did I! :-)

Quite the contrary Alan, I found out that XRD is the only NDE method to do so and then verify using some other conventional destructive method like EPD, TEM, STEM, SEM, etc.

https://www.flickr.com/photos/85210325@N04/10242907544/in/album-72157645018820696/

Hi Ravi Very interesting.  My only thought though is how one can verify the approach.  Tell me there are standards with known dislocation densities...

Mr. Ravi and Mr. Rawle, thank you so much for paying attention to my question. But one of the students in our faculty achieves dislocation density with XRD patterns but i don't know how do it.

Also i know it been achieved by the dislocation density-based constitutive model in the finite element method.

Yours sincerely

http://www.sciencedirect.com/science/article/pii/S1359645414003759

Who is Mr Allen?

i'm so so sorry Mr.Rawle. :-)

Dear colleague Sina Ghaemi Khiavi,

Have a nice time and good day.

The aforementioned discussion of our colleagues @Alan F Rawle and @Ravi Ananth is very interesting. Also you will fined an attach file contains a paper teach you simply how to calculate dislocations density from the XRD patterns.

I wish this is useful and help you.

Yours

A. EL-Denglawey

@A. Eldenglawey  Nice paper.  Thank you for sharing.

Thank you so much Mr E. Elevin , Dr A. Eldenglawey and Dr S.Chander for sharing these useful papers. I really appreciate your helps.

Dear Sina, before u go into that calculation u need to improve ur data quality. As shown in the attached picture ur max intensity is less than 500 cts.

Ur sample is powder or bulk? what is the step scan and scan time?

It can be calculate by PM2K; the software that implement WPPM as mention by Eduard.

To do so u need high quality data and SRM scan to get the instrument broadening.

U cud contact Prof Matteo Leoni for the free software (Maybe the FPA already implemented in the software but this also need the details of inst. setting)

Mr M. Manawan, you mentioned accurate points and i agree with you. But this picture attached so that i express my purpose of question obviously. So this picture isn't a main XRD pattern. My sample is bulk. Could you please give a additional information about maximum intensity, step scan or scan time, if you know?

thank you so much

Well there is no such maximum intensity. In general people refer to the signal to background ratio by monochromatisized the beam.

In practice for Cu-source 40kV/40mA , step-scan equal or less than 0.02, scan-time greater than 2 sec (fast detector easily go up to 20 sec). But it also depend on the nature of your sample; elements, structure, absorbtion, flouresence etc. It is better if u attach a picture after u scan the real data.

Hi

you can use Warren-Averbach method to calculate the density of dislocations.

Dear Dr. Sina. From ur picture, the scan time is too fast. It's a bad data.

Dear Dr. Maykel, i really appreciate your help. I agree with you. Unfortunately, our lab technician is very amateur and these data aren't appropriate for dislocation density calculation so i'm not going to use them.Thank you so much

Dear Dr.Maykel Manawan 

As mentioned, type of materials (powder or bulk) can be effective for calculation dislocation density.please let me know.

Could you please teach me how to calculate dislocation density?

Is that Laue oscillations in XRD pattern ? or Noise in XRD pattern?

since it was a bulk materials processed via HPT (maybe Al, Mg or Fe-based metals), I am pretty sure the aforementioned peaks are noise. However, due to high step-size or fast scanning, the peaks look like oscillations.

Dear Dr Armin. Bulk an powder are suitable for the calculation. The important thing is the data quality (signal to noise ratio). Dont forget to scan the SRM for the instrument profiles.

Dear Xing Fang. Please request the software to Prof. Matteo Leoni. [email protected]. You can tell that the reference is from me because he's very busy since become the Chairman of ICDD.

Warren-Averbach Method for dislocations. Works like a charm

Please do improve the quality of your data though.

The Williamson-Hall modified method is suitable for this.

Dear Sina

You can calculate dislocation density using MAUD software and XRD pattern based on Rietveld analysis.

http://maud.radiographema.eu/

Dear Sina,

You can use 1/D^2 to determine dislocation density where D is the crytallite size calculated using Scherrer's formula