Atomistic Analysis of Unstable Deformation in Amorphous Metal

Abstract

Studying the mechanical properties of amorphous metal is important since materials with non-crystal structure have been drawing attention with their prominent functions. In this paper atomistic simulations of tensile deformation of an amorphous model are conducted and local mechanical instability is analyzed to clarify the deformation mechanism of amorphous structure. Instability causing sharp stress drop is associated with unstable motion of atoms within local region. The size of the region where unstable atomic motion occurs corresponds to the magnitude of total stress decrease. At instability with large stress decrease the deformation at the onset of the instability propagates to surrounding region, which gives rise to relatively large hysteresis loop in the stress-strain relation. This manifests the microscopic mechanism of the plasticity of amorphous structure.