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Dislocation analysis (DXA)

Hello,

I have a relatively large sample with 15,000,000 Cu atoms. I used DXA and exported the dislocation data as Crystal Analysis (CA) files. What I noted is that I cannot use CA files to extract information like dislocation counts and dislocation lengths. So, I have to go through DXA all over again to get this information in tabular form. This is a very time-consuming procedure in my case. Is there any way that I can use CA files to retrieve dislocation counts and dislocation lengths directly?

Thanks a lot!

Reza.

Hi Reza,

Yes, this is a missing feature. There currently is no way to have Ovito calculate the statistical dislocation line lengths from an existing set of CA files. This is something only the DXA modifier does as part of its normal operation.

If you give me a few days, I can extend the CA file reader of Ovito to perform a similar statistical analysis of the line data during data import. Another option for you could be to build and use the following external code, which can postprocess CA files:

https://gitlab.com/stuko/dxa/-/tree/master/

It's something I wrote in the past mostly for internal use. But there is the line_length tool, which is a small standalone program reading in a CA file and outputting the statistical lengths of the different dislocation types. Right now it considers only 1/2<110>, 1/6<112>, and 1/6<110> dislocations though, which means it's only suitable for simulations of FCC crystals. But the code can easily be extended.

-Alex

Thanks a lot, Alexander.

It would be great if you could tackle this problem in the upcoming update of OVITO. I wouldn't complain if my simulations were not that large, but as you know, this size makes everything painful.

Hope to hear from you soon on this matter.

Bests,

Reza.

I've extended CA file reader of OVITO. It will now compute dislocation line statistics during data import similar to the DXA modifier itself. The information is accessible in the data inspector panel. Use the following links to download a preview build of OVITO Basic:

https://www.ovito.org/download/testing/ovito-basic-3.6.0-dev-HEAD-a11825c-win64-cpp17.exe
https://www.ovito.org/download/testing/ovito-basic-3.6.0-dev-HEAD-a11825c-macos-cpp17.dmg
https://www.ovito.org/download/testing/ovito-basic-3.6.0-dev-HEAD-a11825c-x86_64-cpp17.tar.xz

Alex,

Thanks a lot for the extensions. I used them without problem.

I need another advice from you. I am interested in visualizing the evolution of ONLY stair-rod type of dislocations close to an interface, but I was not able to filter out other types of dislocations to see stair-rod dislocations in the simulation cell. Is there any way to visualize one type of dislocation in OVITO?

Bests,

Reza.

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