Atomistic simulations of grain boundary dislocation nucleation

The objective of this research is to use atomistic simulations to investigate dislocation nucleation from grain boundaries in face-centered cubic aluminum and copper. This research primarily focuses on asymmetric tilt grain boundaries and has three main components. First, this research uses molecular statics simulations to examine the structure and energy of these faceted, dissociated grain boundary structures. Second, this research uses molecular dynamics deformation simulations with uniaxial tension applied perpendicular to these boundaries to investigate the relationship between dislocation nucleation mechanisms in asymmetrical boundaries and their faceted, dissociated structure. Third, this research explores the development of models that incorporate the resolved stress components on the slip system of dislocation nucleation to predict the atomic stress required for dislocation nucleation from single crystals and grain boundaries. In summary, the synthesis of various aspects of this work has provided improved understanding of how the grain boundary character influences dislocation nucleation in bicrystals, with possible implications for nanocrystalline materials.