Coalescence and subsequent twinning of nanocrystals during deformation of CuZr-based metallic glasses: The grain size effect

We report in-situ HRTEM observations that reveal subsequent structural events occurring during deformation of CuZr-based metallic glass. During loading, B2-CuZr nanocrystals precipitate and growth in the amorphous matrix, and consecutively crystals larger than 15 nm to 20 nm undergo twinning. Results underscore a transition from a deformation mechanism controlled by shear banding in glassy matrix to twinning and dislocations gliding in precipitated and coalesced crystals. These observations provide guidance for designing metallic glasses with twin structures that improve plasticity. (C) 2017 Elsevier B.V. All rights reserved.