Controlling shear band behavior in metallic glasses through microstructural design

Abstract

Plastic deformation in metallic glasses is governed by the initiation and propagation of shear bands. The successful use of bulk metallic glasses in structural applications will depend on controlling these processes to improve ductility and toughness. In Zr–Cu–Ni–Al metallic glasses, the addition of Ta can influence the structure of the material and hence the shear band behavior in two ways. At low Ta contents (<4 at.%), the material is amorphous but has enhanced order over length scales of 5–15 Å Higher levels of Ta result in the precipitation of bcc Ta-rich solid solution particles in a metallic glass matrix. Under uniaxial compression, both of these materials show greater apparent plastic strain to failure than the glass without Ta. This appears to be the result of the influence of the structure on the initiation and propagation of shear bands in the amorphous matrix.