Universal softening and intrinsic local fluctuations in metallic glasses.

We report a universal softening phenomenon that the shear modulus decreases linearly with increasing the base metal content and verify the local fluctuations, both positive and negative, in metallic glasses. By quantitatively evaluating the fluctuation amplitude, we propose an intuitive physical picture that metallic glasses are atomic level hybrids composed of clusters and amorphous base metals. The local fluctuation characters were further correlated to the mechanical properties of metallic glasses. The study provides insights on the long-standing issues of the atomic level structures, the structure-property relationships, and the mechanisms of plastic deformation and glass transition in metallic glasses. [ABSTRACT FROM AUTHOR]