Calculations of Grain Boundaries with a Parametrized Embedded Atom Method Interatomic Potential

Atomic simulations based on inter-atomic potentials offer a powerful tool for a fundamental understanding of materials processes and properties. The conventional approach for devising an interatomic potential is fitting a set of functions to basic properties obtained from experiments or density functional theory calculations, or both, and using this fit to explore more complex properties. Recently, Daw & Chandross [1] have introduced a comparatively simple parametric functional form based of the Embedded Atom Method for FCC metals. This model takes an inside-out approach, allowing us to generically explore the dependencies of complex properties on the function parameters, and then determining the parameter space that corresponds to a real element. Due to the generic nature of this approach, the model is referred to as EAM-X. In this work, we explore FCC grain boundary (GB) properties in this EAM-X parameter space. We use a representative set of [001] and [110] symmetric tilt, [111] symmetric twist, and [001] asymmetric tilt boundaries. We find that the GB energy can be factored neatly into two parts: one that depends on the boundary parameters evaluated at a chosen reference point in the parameter space, the other being a smooth function of the EAM-X parameters. Generally, the second factor correlates very well with the shear moduli, confirming earlier observations by Holm, Olmsted and Foiles [2], and Foiles [3]. On the whole, our approach provides future avenues to rapidly explore trends in GB properties for a wide range of FCC metals.<br/><br/>[1] M. S. Daw & M. Chandross, “Simple Parameterization of Embedded Atom Method Potentials for FCC Metals” (submitted).<br/><br/>[2] Holm, E. A., Olmsted, D. L., & Foiles, S. M. (2010). Comparing grain boundary energies in face-centered cubic metals: Al, Au, Cu and Ni. Scripta Materialia, 63(9), 905-908.<br/><br/>[3] Foiles, S. M. (2010). Temperature dependence of grain boundary free energy and elastic constants. Scripta Materialia, 62(5), 231-234.