Micro-structural evolution in plastically deformed crystalline materials

Two rate-independent strain gradient crystal plasticity models are developed and applied in numerical studies designed to identify the properties inherent to model predictions of plastic deformation. The two models incorporate gradients of slip into the framework of conventional crystal plasticity in order to model size-dependent plasticity effects. This gradient dependence is achieved by relating a slip measure which combines both slip and their gradients to a shear hardening curve, as commonly done in conventional plasticity theories. Finite element codes are implemented which allow for numerical predictions for the two models to be obtained. Application of the two models to the pure shear boundary value problem is used to characterize plastic behavior, which also allows for the identification of inherent properties through closed form expressions. Single crystal Monazite containing a void is studied through a plane analysis. The conditions that allow for a plane analysis of single crystal Monazite are identified through crystallographic symmetry considerations. Predictions of the slip and micro-structure around a void are presented for size-independent and size-dependent plastic behavior, highlighting the effects due to gradients of slip.