  Precipitation strengthening is one of the most effective methods to design
alloys with the desired combination of strength and ductility. The main
mechanism of strengthening is generally known to be the interaction between
dislocations and precipitates. When a dislocation encounters a precipitate, it
bends and therefore the level of applied stress to the precipitate increases.
Once the applied stress reaches the precipitate resistance, it passes the
precipitate. Dislocations can bypass precipitates either by forming the Orowan
loops or by cutting them. In this research, the focus is set on a small domain
nearby precipitates to investigate their effects on the effective plastic
strain. Both penetrable and impenetrable precipitates are considered. Two
scales are coupled to model this phenomenon, the nano-micro scale where
plasticity is determined by explicit three-dimensional discrete dislocation
dynamics analysis and the continuum scale where the finite element method is
applied. With this hybrid approach, complex problems in plastic deformation of
nanostructured materials can be addressed. Finally, the relation between the
precipitate resistance and the effective plastic strain is investigated.
