Harnessing atomistic simulations to quantify activation parameters for dislocation nucleation from a grain boundary in Nickel

摘要

We perform atomistic simulations and nudged elastic band calculations to quantify activation energy barriers for dislocation nucleation from Sigma 3 grain boundary containing a pre-existing void in Ni. By changing the void size, we offer a phenomenological relationship between the activation free energy at zero stress and boundary porosity. Simulations at different temperatures are also conducted to gain some insights into the inherent intricacies of activation energy landscape. It is envisioned that the approach can be pushed forward to guide the flow rules of physics based crystal plasticity models at higher length scales that account for grain boundary effects. (C) 2020 Elsevier B.V. All rights reserved.