Elastoplasticity

Abstract

Plasticity attributed to dislocation motion in crystals is considered in detail in Chapter 6. In many crystalline solids, large deformations are not sustainable by thermomechanically recoverable deformation alone. Deviatoric elastic deformations generate shear stresses, which, when large enough, facilitate generation and motion of lattice defects. More specifically, ductile crystals tend to exhibit plastic deformation arising from generation and glide of dislocations (e.g., dislocation lines and loops) when subjected to deviatoric stresses exceeding some mechanical threshold, elastic limit, or yield point. Thermally activated dislocation motion (e.g., kink migration) is possible even when resistance in isolated locations (e.g., in the vicinity of obstacles such as heterogeneities) to glide exceeds the magnitude of average resolved stress acting on a glide plane in the slip direction.