On the characterization of plastic flow in Zr-based metallic glass through micro-indentation: An atomic force microscopy analysis

We report an atomic force microscopy analysis of multiple shear bands emerged under multiaxial deformation through micro-indentations of Zr60Ni10Cu20Al10 metallic glass forming system. Both relative variations of normal and lateral force components as a result of contact between a Si3N4 tip mounted on a cantilever beam and incomplete circular pattern features developed around indentation are recorded at the nano and micro-length scales. Accurate three-dimensional measurements of shear offset as function of position along the shear band and the loading charge in the range of 0.5 to 5 N are determined. Evidence for propagation of discrete displacement increments is shown. Numerical calculations based on the well defined strain localization model including hydrostatic pressure effect on elastic variation of the average free volume are developed to explain the incomplete circular patterns of shear bands observed under constrained deformation.