From electrons to atoms: Designing an interatomic potential for Fe-C alloys

This chapter presents the case study of bridging the two lowest length scales within the Integrated Computational Materials Engineering (ICME) paradigm, namely, the electronic and atomic scales, using the case of developing an interatomic potential for Fe-C alloys. It proposes 2NN MEAM potential model for the Fe-C alloy system by optimizing the MEAM parameters to reproduce the structural and elastic properties of cementite as predicted by density functional theory (DFT), which is a method to calculate the electronic structures and their attributes. Using the Fe and C single-element potentials, we obtained the most optimal parameterization of the alloy potential of Fe-C for the purposes specified by the objective function that takes into account various properties of Fe-C alloys. The chapter presents structural properties of cementite including the equilibrium lattice parameters, the equilibrium volume per atom, and the heat of formation with comparison to DFT/experiment and other interatomic potentials.