Stick-slip instabilities in a Zr-based bulk metallic glass

At temperatures well below the glass transition, plastic deformation of bulk metallic glasses is characterised by a strong degree of flow localisation and the formation of narrow shear bands. The mechanism by which shear bands form and operate remains subject of debate. We can show that serrated flow observed during compression testing of bulk metallic glasses is remarkably similar to other stick-slip systems. While a common property of these systems seems to be their disordered nature, they essentially bridge a wide range of underlying dimensions, from macroscopic to atomic length scales. The dynamics of individual slip events in a Zr-based metallic glass can be captured by time-resolved compression testing. A careful analysis reveals a wide distribution of event duration in agreement with chaotic dynamical behaviour. A correlation between event amplitude and duration can be established. The results are discussed by applying conventional stick-slip theory to the inhomogeneous deformation behaviour of metallic glasses.