1, Metal Physics and Technology, ETH Zurich, Zurich, , Switzerland
The mechanical properties of bulk metallic glasses are strongly influenced by their disordered microstructure, which generates inhomogeneous deformation at low homologous temperatures with confinement into localized shear bands. The operation of these bands is intermittent, as reflected in serrated flow curves, and can be understood in the context of stick-slip motion, in which extended periods of arrest are followed by rapid slip events. Such processes also occur across macroscopic length scales ranging from granular systems to tectonic faults. In this talk, I will present our studies on the composition dependence of shear-band stability, which we obtained via an evaluation of the temperature-dependent shear-band velocity for a variety of metallic glasses. I will show that the shear resistance of metallic glasses is determined by the constituent-specific bond energies of their topological atomic motifs. The model reveals robust scaling for all alloys and provides detailed insight into the underlying atomistic origins of shear stability and shear-barrier energy. It also identifies procedures for the design of ductile metallic glasses, which are summarized in a design map involving shear modulus and Poisson’s ratio.