Effect of residual shear bands on serrated flow in a metallic glass

This work studies the effects of the shear bands on serrated flow of the metallic glass Zr-5Ti-17.9Cu-14.6Ni-10Al using nanoindentation technique and scanning electronic microscopy (SEM). It was observed that the nanoindentation load-displacement (P-h) curves are serrated when the nanoindents were made within the region had pre-introduced shear bands from a spherical indentation made with higher load in the specimen. The results support the earlier observation and assumption that the pre-introduced shear bands intersect with the new shear bands induced by nanoindentations, leading to less pile-up around the nanoindentation impressions. This result is discussed with possible mechanisms of the plastic deformation of the metallic glass materials.