NOMAD Laboratory


Jul 16, 2018

New, Open Access Grain Boundary Tools from NOMAD

The NOMAD teams in KCL and University of Warwick have published new open access resources for the Imeall package, used to compute and index the atomistic properties of grain boundaries. The resources described are available online and can be extended by any user (Imeall: A computational framework for the calculation of the atomistic properties of grain boundaries, H. Lambert, A. Fekete, J.R. Kermode, and A. De Vita, Computer Physics Communications (2018), In Press). 

The Imeall 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.

The resource is offered online as fully open-access and is extensible by any user. The code repository can be found at https://github.com/kcl-tscm/imeall, links to the full structure database, which is hosted on the NOMAD servers and the web framework can be found in the documentation of the package at http://kcl-tscm.github.io/imeall/index.html. The database is stored on the NOMAD servers and can be navigated indirectly via http://imeall.co.uk/ or directly via https://labdev-nomad.esc.rzg.mpg.de/industry-project-imeall/. The server space is reserved for the next 10 years which provides a mid- to long-term platform for storage of structures and public accessibility.

Figure 1. The general coordinate system for determining tilt and twist boundary planes and orientations using quaternion algebra.