Structural, elastic and thermal properties of cementite from Modified Embedded Atom Method (MEAM) potential*

Structural, elastic and thermal properties of cementite were studied using a newly developed MEAM potential for the Fe-C alloy system. The single element potential of C correctly predicts graphite and diamond as the two stable structures. Parameters for the Fe-C alloy potential were constructed based on the structural and elastic properties of elements in the L$_{\rm{12}}$ reference structure, calculated from ab-initio simulations. Parameters were further adjusted to reproduce structural properties of cementite and the interstitial energies for Fe correctly. Pair potential parameters were optimized using a method combining Latin hypercube sampling of the N-dimensional parameter space and multi-objective optimization. Elastic constants, surface formation energies, melting temperature and specific heat of cementite were calculated using the potential. The values computed from the Fe-C alloy MEAM potential are in good agreement with DFT calculations and experiments.