With the increasing use of molecular simulation to understand deformation mechanisms in transition metals, it is important to assess how well the simulations capture behavior both near equilibrium and under more extreme conditions. In particular, it is important to assess whether, for any of the interatomic potentials, unphysical deformation paths may be competitive with those generally observed. In this work we compare generalized planar fault energy landscapes and surface energies for various interatomic potentials with those from density functional theory calculations to examine how well these more complicated planar faults and surface energies are captured and whether any deformations are energetically competitive with those observed in fcc crystals. We examine not just the (111) orientation, but also the (100), (110), (210), (211), (311), and (331) orientations to test behavior outside of the fitting range of the interatomic potentials. We find that the shape of the (111)[1 1 -2] stacking fault energy curve varies significantly with potential and some deformation paths for non-(111) orientations give activation barriers less than 50\% higher than the unstable stacking fault energies. These are important considerations when choosing an interatomic potential for deformation simulations.
Citation: Philosophical Magazine A-Physics of Condensed Matter Structure Defects and Mechanical Properties
Pub Type: Journals