Microscopic mechanisms of shear band formation in bulk metallic glasses

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The mechanical properties of bulk metallic glasses (BMG) are intimately related to the formation of shear bands when these materials are deformed. In this project, large-scale Non-equilibrium Molecular Dynamics (NEMD) simulations are used to study the microscopic mechanisms of shear banding in BMG. Simple model systems are considered to understand generic scenarios of shear banding in glasses. Moreover, realistic models (in particular for Pd40Ni40P20) are developed by means of ab initio calculations. Then, by analyzing self-diffusion, strain maps and structural anisotropies inside and outside the shear bands, NEMD simulations with the realistic models allow for a direct comparison to the results obtained in the experimental project. The project’s primary focus is to give insight into the formation of shear bands via local plastic events (such as shear transformation zones). Furthermore, nucleation of fracture processes from shear banding shall be investigated. To achieve this, various parameters of the simulation are systematically changed, using different protocols of compression and shear, the consideration of simulations at constant volume and constant pressure, and the consideration of glass samples resulting from quenches at different cooling rates.