Abstract
We describe the Imeall package for the calculation and indexing of atomistic properties of grain boundaries in materials. The package provides a structured database for the storage of atomistic structures and their associated properties, equipped with a programmable application interface to interatomic potential calculators. The database adopts a general indexing system that allows storing arbitrary grain boundary structures for any crystalline material. The usefulness of the Imeall package is demonstrated by computing, storing, and analysing relaxed grain boundary structures for a dense range of low index orientation axis symmetric tilt and twist boundaries in α-iron for various interatomic potentials. The package’s capabilities are further demonstrated by carrying out automated structure generation, dislocation analysis, interstitial site detection, and impurity segregation energies across the grain boundary range. All computed atomistic properties are exposed via a web framework, providing open access to the grain boundary repository and the analytic tools suite. Program summaryProgram Title:ImeallProgram Files doi:http://dx.doi.org/10.17632/nj77stc62b.1Licensing provisions: Apache-2.0Programming languages: python, fortran, javascriptNature of problem: Determining the minimum energy structure for a specific grain boundary and interatomic force field involves extensive searches in configuration space. Duplication of this effort should be avoided, and providing a unique database to gather the resulting structures is needed for this. Accurately cataloguing the chemical and electronic environments associated with the interface atoms in the grain boundary furthermore requires a useable interface between a database of grain boundary structures and an expandible set of interatomic potential calculators.Solution method: We introduce a standard indexing convention that allows the integration of grain boundary structures for arbitrary materials, generated by different users/research groups, into a normalised database that can be easily queried and used as a starting point for further research projects. The Imeall package accomplishes this by specifying a standard naming convention for the grain boundary database and by providing the software routines necessary to populate and query such a database, as well as an interface to interatomic calculators and analysis tools.
Highlights
Solution method: We introduce a standard indexing convention that allows the integration of grain boundary structures for arbitrary materials, generated by different users/research groups, into a normalised database that can be queried and used as a starting point for further research projects
Having access to a standardised database of grain boundary structures is an important prerequisite for any atomic-scale (‘‘chemo-mechanical’’) analysis, e.g., to investigate how impurities trapped at grain boundaries influence the mechanical strength of the material
We have described the structure and function of the Imeall package
Summary
Evaluating several properties of significant engineering interest requires access to the atomistic structures of grain boundaries These include, but are by no means limited to, the diffusivity of impurities at grain boundary interfaces [1], the segregation energies of impurities to interfaces [2], and the interaction and slip transmission of dislocations across boundaries [3,4]. This scheme allows the database to incorporate grain boundary structures for any reference crystalline material, computed using any interatomic potential, in a consistent and physically intuitive fashion.
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