In situ deformation in the transmission electron microscope (TEM) has provided great insight into the fundamental mechanisms governing deformation of crystalline materials. The reason is the possibility to image the fundamental carriers of plasticity, namely dislocations. For metallic glasses (MGs), however, their disordered amorphous structure makes it challenging to reveal the most fundamental deformation events. Therefore, in situ deformation of MGs typically only captures catastrophic shear events but provides little experimental evidence on the early stages of strain localization. While the disordered nature of MGs impedes directly imaging their atomic structure, 4D-STEM using nanobeam electron diffraction allows to obtain quantitative information on a local scale, for example the elastic strain field [1]. Here we show that strain mapping can help to reveal fundamental deformation mechanisms in MGs and thus provide a more direct link between structure and properties of amorphous materials.

[1] C. Gammer, J. Kacher, C. Czarnik, O. L. Warren, J. Ciston, and A. M. Minor, Appl. Phys. Lett. 112, 171905 (2018).

We acknowledge support from the Austrian Science Fund (FWF):Y1236-N37.