Localized deformation of a Cu_46.25Zr_45.25Al _7.5Er₁ bulk metallic glass

Using the cavity model and the concept of the plastic-hardening modulus, a simple relationship was established between the size of an indent and the size of a semi-spherical-shell softening zone. Indentation experiments of a Cu _46.25Zr_45.25Al_7.5Er₁ bulk-metallic glass (BMG) were performed over a range of indentation loads from 500 to 4000 mN, using a Vickers indenter. The indentation hardness decreased slightly with the increase in the indentation load from 5.21 GPa at an indentation load of 500 mN to 4.66 GPa at an indentation load of 4000 mN. The evolution of shear bands underneath the indentation was studied using an interface-bonded BMG sample. Shear bands of a semi-spherical-shell shape and a line-shape were observed underneath the indentation. The dependence of the size of the shear-banding zone on the size of the indent was examined, which qualitatively supported the analytical model. The inter-banding spacing decreased with the increase in the indentation load, associated with the release of the stored strain energy.