Density functional theory-informed dislocation density hardening within crystal plasticity: Application to modeling deformation of Ni polycrystals

In the present work, the flow response of polycrystalline Ni as a function of grain size is captured using a crystal plasticity fast Fourier transform (CPFFT) model with a dislocation density (DD) hardening law. In order to increase the robustness of the DD model, two of its parameters that are typically fit to experimental data, the normalized activation energy for overcoming the dislocation glide barrier and the generation rate of dislocation debris at high levels of strain, are obtained from first-principles calculations based on density functional theory (DFT). These parameters are related to stacking fault energy and vacancy formation energy, both of which can be accurately predicted by DFT-based calculations. The present work demonstrates a successful integration of DFT results into the DD hardening law within CPFFT, facilitating parameterization and reducing the uncertainties of calibration to macroscopic flow response.