Characterization of mechanical properties of a Zr-based metallic glass by indentation techniques

This paper presents studies on mechanical properties of a Zr-based metallic glass by using spherical indentation and nano-indentation techniques. The spherical indentation investigates mechanical properties of the Zr-based metallic glass as a function of indentation strain. The results show that the Zr-based metallic glasses have almost perfect plasticity with little strain hardening. During fully plastic stage, spiral shear bands appear inhomogeneously around the impression of the spherical indentations. The shear bands initiate from the impressions at an angle slightly deviating from the pure shear stresses in the free surface. Further nano-indentations by using Berkovich tip made around the spherical indentation impression show that there is a zone of lower hardness around the impression of the spherical indentation. SEM and AFM images show that there exists significant different pile-up behaviors of the impressions by the nano-indentation far away and near the spherical indentation impression. Near the spherical indent, less pile-up is formed around the impression of nano-indentation, and this is assumed to be the result of the intersection between the pre-introduced shear bands by the spherical indentation and the new shear bands induced by nano-indentation.