Enhancing the plasticity of metallic glasses: Shear band formation, nanocomposites and nanoglasses investigated by molecular dynamics simulations

Abstract

We investigate the influence of various microstructural features on the deformation behavior of binary Cu64Zr36 glasses by molecular dynamics computer simulations and discuss how and why the very same modifications established for enhancing the strengths of crystalline materials, namely the insertion of solutes, precipitates and grain boundaries, can be used for tuning the mechanical properties of metallic glasses. First, by testing bulk samples with and without open surfaces under tensile load, we show that the condensation of shear transformation zones into shear bands can occur as heterogeneous but also as a homogeneous nucleation process. Then, the influence of crystalline nanoprecipitates on shear band nucleation and propagation is investigated. Finally, we study the effect of grain size and composition on the deformation behavior of nanoglasses and nanoglass composites. The results reveal that glass–glass interfaces act as structural heterogeneities ,which promote shear band formation and prevent strain localization.