Plastic Deformation of Crystals: Plastic deformation of crystalline solids, including ordered compounds and multiphase materials, is investigated. Strain localization is studied under multiple slip deformations. Nonlocal effects that give rise both to size-dependent phenomena and patterning of localized flow are also investigated utilizing both continuum theories and discrete dislocation simulations. Interface Mechanics: The relationship between atomic-level (discrete) and continuum properties of heterogeneous solids is studied. In particular, the spatially-varying (anisotropic) elastic properties of interfaces and their effect on lattice vibrations (phonons) and localized waves are investigated. The implication of distinct atomic structures on interface diffusion is being explored in relation to another current interest in decohesion along interfaces. Fracture: Fracture along interfaces is studied from several perspectives with recent interest in dynamic embrittlement arising from impurity diffusion. Atomistic simulations are utilized to guide the continuum modeling of this thermodynamically non-equilibrium process. Models for crack propagation are being developed and compared with experiments.
