Shear Banding Observed in Real-Time with a Laser Speckle Method

In many high-strength materials, such as in metallic glasses, localized deformations can lead to quasi-brittle behavior where the amount of energy dissipated by mechanical deformation prior to material failure is small, as only a small volume fraction of the material deforms inelastically. Thus, techniques that allow observations of localized deformations at relevant length and time scales are instrumental in order to engineer such materials. Here, a real-time optical system based on high-speed imaging of laser speckle is applied to the propagation of shear bands in metallic glass. The quality and accuracy of information obtainable by this technique as well as its applicability to study important aspects of shear banding in metallic glasses are discussed and a comparison with more conventional approaches are presented.