Critical length scales for the deformation of amorphous metals containing nanocrystals

Shear localization is studied in simulated amorphous systems containing individual nanocrystalline inclusions. Systematic variation of the inclusion diameter and the shear band thickness reveals a crossover in length scales that separates distinct plastic flow mechanisms in and around the nanocrystalline inclusion. When considered relative to the shear band thickness, small inclusions deform via heterogeneous, interface-dominated mechanisms, while large inclusions yield via the homogeneous nucleation of dislocations in the nanocrystal interior; nanocrystals roughly twice as large as the shear band width are required for the strongest interaction.