MOLECULAR-DYNAMICS STUDY OF STRUCTURAL ANISOTROPY AND ANELASTICITY IN METALLIC GLASSES

Molecular-dynamics simulations have been carried out to study the structural anisotropy in anelastically deformed glassy metals. Two model glass structures, a single-component glass of 4394 particles interacting via a modified Johnson potential and a two-component glass of 2048 particles with the Lennard-Jones potentials, were thermomechanically deformed below their glass-transition temperature. The structural anisotropy caused by anelastic deformation is dominated by the bond-orientational anisotropy (BOA) with a large sixth-order spherical-harmonic component in both model structures. The sixth-order BOA could be associated with the local bond-orientational order (BOO) of the basic local structural units, such as tetrahedral and icosahedral clusters. We propose a scheme to describe the structure of the glasses and their mechanical properties, based upon the sixth-order local BOO.