Multi-scale modeling of dislocation processes

Connecting microscopic mechanisms of deformation to macroscopic behavior requires an appropriate formalism that bridges the length scales of these processes. We propose a simple constitutive relation relating dislocation velocity to the net force that provides a formalism for the incorporation of specific dislocation mechanisms into the description of global plastic deformation. We then employ this approach to describe macroscopic deformation behavior controlled by forest intersection. An activation volume tensor and the activation enthalpy for deformation now become functions of the three-dimensional state of stress. Concepts presented in this work provide a framework for further development of multi-scale computational models that bridge length scales in the description of plastic deformation.