We present an analytical bond-order potential for the Fe–O system, capable of reproducing the basic properties of wüstite as well as the energetics of oxygen impurities in α-iron. The potential predicts binding energies of various small oxygen-vacancy clusters in α-iron in good agreement with density functional theory results, and is therefore suitable for simulations of oxygen-based defects in iron. We apply the potential in simulations of the stability and structure of Fe/FeO interfaces and FeO precipitates in iron, and observe that the shape of FeO precipitates can change due to formation of well-defined Fe/FeO interfaces. The interface with crystalline Fe also ensures that the precipitates never become fully amorphous, no matter how small they are.

Sponsoren: The research has been carried out with financial support from the Academy of Finland (project MIMOSE, Contract No. 259249). This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Grants of computer capacity from CSC—IT Center for Science, Finland, as well as from the Finnish Grid and Cloud Infrastructure (persistent identifier urn:nbn:fi:research-infras-2016072533) are gratefully acknowledged.