Densification and heterogeneity enhancement of Fe-based metallic glass under local plastic flow

Abstract

The atomic-scale structure and concomitant mechanical property evolution of a ribbon-shaped Fe₇₈Si₉B₁₃ metallic glass after local plastic flow are investigated. By using abrasive papers as a medium to transport the pressure, the equivalent pressure on the ribbon surface is sufficiently magnified. Multiple shear bands pervading along their surface are generated simultaneously after deformation. The densification processes triggered by the cooperative atomic rearrangements in the short and medium-range are revealed by analyzing the synchrotron diffraction patterns in reciprocal space and real space. Meanwhile, the local plastic flow enhances the structural heterogeneity. In contrast to the strain-softening under uniaxial loading, these structural changes contribute to the improvement of resistance to subsequent deformation. As a result, the Vickers hardness of the deformed Fe₇₈Si₉B₁₃ metallic glass increases compared with the undeformed sample, manifesting a local strain-hardening behavior.