Mutual interaction of shear bands in metallic glasses

Shear banding is the main plastic deformation mode in metallic glasses. Even though there are many researches focused on the initiation and propagation of shear bands, the interaction among them has not been systematically studied. Using an atomic force microscope, we investigated the mutual interaction of shear bands at the surface of Cu₅₀Zr₅₀ metallic glass ribbons at the nanoscale. At the sites of the interaction, the propagation direction of one shear band can be changed by the pre-existing one, and the offset is the vector sum of the two bands. Under external stress, one shear band can be decomposed into several tiny bands and more materials could be taken into the deformation zones. Therefore, more energy can be dissipated and the deformation could be more homogeneous for the mutual interaction process. These results are useful for a mechanistic understanding of the evolution and suppression of shear band propagations, as well as the design of metallic glasses with improved plasticity.