What tools are used for the preparation of grain boundary models?

What methods and tools are used for building models of grain boundaries?
I mean initial models that are then optimized using molecular dynamics potentials or a different methods.

When I was involved in such things 10-15 years ago we were writing own codes to generate starting structures. Both big systems that emulated nano-sized policrystals

and small bicrystals to analyze particular boundary types

(I added pictures to clarify what type of things I'm writing about)

I wonder what tools (if any) are used nowadays?

• Czeszc Marcin! "grain-boundaries" is one of the only tags we don't have a description for yet, would you mind filling it out here? materials.stackexchange.com/edit-tag-wiki/26 Your edit will be placed in a queue and I will accept it if it makes sense :) May 6 '20 at 4:07

If you are looking for generating synthesized microstructures for using it in Phase-Field simulation, the best choice is Dream 3D, where you can control the distribution of grains and their crystallographic orientations:

If you are looking for a framework to generate synthesized polycrystalline structures for molecular dynamics simulation, the best tool is Atomsk, that is compatible with LAMMPS, DL_POLY, VASP, QuantumEspresso, SIESTA, etc.:

• Can Atomsk generate bicrystal models for analysing particular types of grain boundaries like CSL/special boundaries ($\Sigma 3$, $\Sigma 5$, etc.)? May 5 '20 at 11:30
• @Mythreyi Not directly as far as I know. May 5 '20 at 19:48

Alone Programmer's answer already mentions ways to generate polycrystalline microstructure. To add to that, it is possible to generate models of bi-crystals to analyse particular grain boundaries directly using LAMMPS. Here is a detailed wiki on how to generate such models.

Apart from this, there was a Java based applet called GBStudio that made generating grain boundary models very simple. Unfortunately, this tool seems to be no longer available.

In 2008 I wrote a Python script to generate bicrystal models in a PBC box.
Since the boundary is periodic (due to PBC), it's always a coincidence site lattice (CSL) boundary.

The script is in repository named gosam and is documented here.

The math was based on H. Grimmer's paper "The generating function for coincidence site lattices in the cubic system", so it works only for cubic lattices.

From time to time (maybe once every two years) I get a question from someone trying to use this script. Unfortunately, I don't remember much and I can only answer simple questions.