Plastic flow in bulk metallic glasses: Effect of strain rate

An analysis is presented for the onset of plastic deformation in bulk metallic glasses. It is based on the hyperbolic sine flow law and the introduction of a parameter describing the density of flow units over shear plane. The resistance to the onset of the plastic flow in bulk metallic glasses is found to follow the Mohr-Coulomb-like dependence on effective normal stress and depend on strain rate. A semianalytical relation is established between the nominal serrated size and the serrated stress for serrated flow present in uniaxial tests when subjected to constant strain rates. The analysis is in good accord with experimental results reported in literature.