Multi-scale Modeling of Plasticity Nearby Precipitates in Nanostructured Materials

Abstract: 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.