A first-principles based multi-scale single-crystal plasticity model for face-centered cubic metals was presented, and applied to nickel. The model consisted of a phase-field approach to dislocation dynamics, with all of the input parameters being obtained from equilibrium and non-equilibrium molecular-dynamics simulations. The atomistic information used to inform the phase field model included elastic constants, dislocation core energy, crystal disregistry energy (gamma surface), and dislocation mobility. It was shown that the phase-field dislocation-dynamics model could be simplified to the Frenkel-Kontorowa equations for straight dislocations, and under these conditions an analytical time-dependent solution enables a direct connection to non-equilibrium molecular-dynamics simulations. This time-dependent analytical solution provided a relationship between dislocation mobility (ratio between dislocation velocity and applied stress) and fundamental atomic-scale materials properties that arose from the atomistics: unstable stacking fault energy and dislocation core energy and width. It was found that the dislocation mobility increased linearly with the ratio between the core energy and unstable stacking fault energy in the phase-field dislocation-dynamics theory.

Effect of Core Energy on Mobility in a Continuum Dislocation Model. D.W.Lee, H.Kim, A.Strachan, M.Koslowski: Physical Review B, 2011, 83[10], 104101