Engineering alloys are usually heterogeneous and contain a high density of interfaces such as grain boundaries (GBs). When subjected to plastic deformation, the behavior of these materials is largely dictated by the interaction between the dislocation-mediated slip and those interfaces. Due to the length-scale limitation, a fully atomistic model usually can only accommodate a few dislocations without considering much material microstructure complexities. In contrast, starting from the principles of statistical mechanics, our concurrent atomistic-continuum (CAC) approach unifies the atomistic and continuum description of materials within one single framework. It can accommodate the long-range dislocation slip and the atomically structured interfaces all within one model. In this talk, I will present our recent development of an adaptive CAC for predicting slip transfer in plastically deformed polycrystalline alloys with its grain size spanning from nanometers to micrometers. The slip-interface reaction-induced complex internal stress as well as its contributions to the subsequent structure changes, such as lattice rotation, twinning (nucleation, growth, variant selection), phase transformation (PT), and reverse PTs, will be characterized from the bottom up. The obtained results can be then informed into a local stress- or couple stress-based slip transfer metrics. An implementation of such metrics in higher length scale models, such as crystal plasticity finite element (CPFE), will significantly improve their predictive capability from the bottom up. This in turn, will lead to an atomistic-to-macroscale computational platform that can be used for predicting the microstructure evolutions in a variety of engineering materials exposed to extreme stresses, corrosive, irradiations, and even a combination of them.
Copyright. All Rights Reserved.