Atomistic mechanisms of cyclic hardening in metallic glass

Molecular dynamics with an embedded-atom method potential is used to simulate the nanoindentation of Cu[subscript 63.5]Zr[subscript 36.5] metallic glasses. In particular, the effects of cyclic loading within the nominal elastic range on the overall strength and plasticity of metallic glass are studied. The simulated results are in line with the characteristics of experimentally observed hardening effects. In addition, analysis based on local von Mises strain suggests that the hardening is induced by confined microplasticity and stiffening in regions of the originally preferred yielding path, requiring a higher applied load to trigger a secondary one.United States. Office of Naval Research (Grant N00014-08-10312