The secondary (β) relaxation is an intrinsic feature of glassy systems and is crucial for the mechanical properties of metallic glasses. However, it remains puzzling what structural features control the β-relaxation fundamentally. Here, we use the recently developed nanoglasses exhibiting well-defined structural features at the nanometer scale to interrogate such structure-dynamics relations. We show that an electrodeposited Ni77.5P22.5 nanoglass exhibits promoted β-relaxation and enhanced microscale tensile plasticity over the most rapidly melt-quenched metallic glass with the same composition. Structurally, the β-relaxation is sensitive to the interfacial regions among grains in the nanoglasses. Our results reveal a clear correlation between the amorphous nanostructures and the β-relaxation. It seems that the nanostructuring represents a novel route to obtain high-energy glassy states, that is, the inverse problem of the ultrastable glass.
Keywords: Metallic glass; mechanical properties; nanoglass; secondary relaxation.