Despite their unique properties, metallic glasses show limited ductility at room temperature. The improvement of mechanical properties is induced by the introduction of secondary crystalline phases or highly rejuvenated regions. This renders deformation mechanisms in metallic glasses even more complex. A fundamental understanding is still lacking. 

In this work, we provide direct insight into the evolution of local elastic and global plastic strain fields during in-situ deformation. Strains are measured in amorphous and crystalline domains simultaneously at the nanoscale. We use a 4D-STEM setup incorporating an in-column energy filter in combination with a fast direct electron detector. 

Due to the emergence of dedicated specimen holders and novel MEMS systems, in-situ TEM measurements are a powerful tool allowing to directly measure the effect of structural heterogeneities on properties of these tailored metallic glass composites. 

This work was supported by the Austrian Science Fund (FWF): Y1236-N37