Hierarchical Modeling of Failure Mechanisms and Grain-Boundary Effects in Nanocrystalline Aggregates

New hierarchical computational methodologies have been developed to predict dominant material behavior and mechanisms at scales ranging from the nano to the macro. Physically based scaling relations have been developed to characterize mechanisms and grain-boundary effects in nanocrystalline materials. These scaling relations have been used to link molecular dynamic and microstructural finite-element techniques to delineate the interrelated effects of grain boundary orientation and structure, grain- boundary sliding and friction, and dislocation transmission, absorption, and blockage through GBs, such that dominant failure mechanisms can be accurately identified and predicted from initiation to unstable growth. .