Understanding the coupled influence of sub-glass-transition ( T g ) annealing and alloying on plastic flow in metallic glasses (MGs) remains a challenge because structural relaxation and compositional complexity simultaneously change the local atomic environments which govern shear activation. Here, we combine high-energy X-ray total scattering, differential scanning calorimetry, nanoindentation, and molecular dynamics to establish a structural-state description that links local structure to deformation behavior in Cu-Zr-(Al/Ag/Ti) MGs. Sub- T g annealing and increased compositional complexity sharpen the primary peak of the pair distribution function, produce a small dilation of the nearest-neighbor distance, increase the peak-position ratio, and the fraction of quasi-icosahedral local environments, while reducing the magnitude and spatial connectivity of excess free volume. These coupled changes are summarized by a structural coordinate R , constructed from descriptors of short-range structural ordering, relaxation enthalpy, and local atomic packing, and validated on the alloying-order-swapped alloys using the same calibration. The indentation response varies systematically with this structural-state description: strain-rate sensitivity increases with R , whereas the shear activation volume decreases. Intermittent plasticity also weakens with relaxation, and serration energies and large displacement burst events diminish as the connected plastic-zone footprint contracts. The results show that chemistry primarily determines the initial atomic structure and the capacity for sub- T g relaxation, while annealing progressively drives the MG toward a more relaxed structural state, providing a comparative basis for relating strain-rate sensitivity and the spatial correlation of plasticity to structural state in Cu-Zr-based MGs.
Bajpai et al. (Fri,) studied this question.
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