Author Topic: How to generate nanocrystalline structure using voronoi tessellation?  (Read 1759 times)

majid.mgd

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Dear all,

I have recently started working with OVITO and I’m working on nanocrystalline structures.
My current challenge is to generate a 3d crystalline structure using voronoi tessellation.
Does OVITO generate voronoi tessellations on a box of atoms just by taking the position of atoms as inputs?
What kind of process should I perform on atoms to prepare the appropriate input file for OVITO to generate (or visualize) a nanocrystalline structure with grain boundaries? (if it’s needed.)

Thanks for your answer, Majid Moghaddam

Alexander Stukowski

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Re: How to generate nanocrystalline structure using voronoi tessellation?
« Reply #1 on: March 20, 2017, 08:40:55 AM »
Hi Majid,

No, Ovito cannot generate atomistic models of polycrystalline microstructures for you. Please don't confuse the Voronoi analysis function of Ovito with a "Voronoi crystal generator". The former constructs the Voronoi cell around each atom for characterizing the local atomic coordination, while the latter constructs the Voronoi cells for a given set of points in space (the "grain centers") and fills them with atoms on differently oriented crystal lattices.

Years ago I wrote my own Voronoi crystal generator code to produce initial starting configurations for my work on nano crystalline metals, but I think nowadays several codes have been published that provide ready-to-use solutions. Here is one example from a group in Germany that came to my mind:

http://www.gmp.ww.uni-erlangen.de/nanoSCULPT.php

You also asked for the reverse process: How to reconstruct the grain boundaries from an atomistic model of a polycrystal. Such a "grain segmentation algorithm" is being developed for Ovito, but it's not publicly available yet. I still haven't found the time to finish the work.

majid.mgd

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Re: How to generate nanocrystalline structure using voronoi tessellation?
« Reply #2 on: March 20, 2017, 10:14:41 AM »
Hi Dr. Stukowski,

Thank you for your answer. you're right! I actually confused the Voronoi analysis function of Ovito with a voronoi crystal generator! but now thanks to your advice, I think I know where to start from. and good luck with developing the "grain segmentation algorithm".

Regards, Majid