Connecting interatomic potential characteristics with deformation response in FCC materials

L Smith and D Farkas, COMPUTATIONAL MATERIALS SCIENCE, 147, 18-27 (2018).

DOI: 10.1016/j.commatsci.2018.01.055

We present a molecular dynamics study using six different FCC model embedded atom method interatomic potentials. We investigate the relationship between specific interatomic force law properties and the deformation response of nano-scale grain boundary networks. We used a fully periodic quasi three-dimensional sample with random 1 1 0 tilt boundaries, adjusted for the lattice parameter of each potential. This procedure enabled the study of deformation behavior differences to be attributed to the potential used. The interatomic potential characteristics of cohesive energy, elastic constants and stable and unstable stacking fault energies were correlated with grain boundary structure and energy, the yield and flow stress, and the contributions to plasticity from dislocation emission and grain boundary sliding. We find non-planar features in the grain boundary structure for interatomic potentials characterized by low stacking fault energy. In turn, these non-planar features in the grain boundary hinder grain boundary sliding deformation mechanisms. Dislocation emission from the grain boundaries is controlled by the unstable stacking fault energy. The overall yield and flow stresses observed for these nano-scale grain boundary networks correlate with the unstable stacking fault energy given by the potential. (C) 2018 Elsevier B.V. All rights reserved.

Return to Publications page