Characterization of flow units in metallic glass through density variation

The evolution of flow units associated with the flow defects in metallic glass is characterized by monitoring the metallic glassy density change upon isothermal annealing far below their glass transition temperature. A meaningful function for the density variation with the concentration of flow units is obtained for the metallic glasses. We show that the correlation between the density variation and the flow unit have implications for understanding the fragility, structural heterogeneous, and structural relaxation behaviors in metallic glasses. (C) 2013 AIP Publishing LLC.