Direct observation of Eshelby inclusions in metallic glasses

Abstract The application of metallic glasses is limited by their catastrophic failure during shear banding. The shear transformation zones (STZs), which are theoretically defined as Eshelby inclusions plastically deformed in glassy matrix and responsible for the shear banding, have not been directly observed in experiments for metallic glasses. This hinders the establishment of the deformation theory and new material designs. With this work, we solved the longstanding difficulty of experimental visualization of the STZ phenomenon in metallic glasses, by correlatively imaging strain fields and atomic packing density at the nanoscale using 4-dimensional scanning transmission electron microscopy. The results for the first time show the quadrupolar strain field surrounding dilated nano-volumes aligned on a shear band. This opens a new door for research on metallic glasses.