Annealing‐Induced Plasticity and Strengthening in Metallic Glasses

ABSTRACT Annealing‐induced embrittlement has long been considered unavoidable in metallic glasses because it annihilates free volume (i.e., locally loosely‐packed regions, LLPRs) required for plasticity. Here, we overturn this paradigm by demonstrating that sub‐ T _g annealing simultaneously increases both the strength and compressive plasticity of a chemically tailored Zr‐based metallic glass, with plastic strain increasing by >150%. Our experimental analyses reveal that strategically employed Ni─Cu repulsion drives elemental partitioning during annealing, which seeds nanoscale chemical heterogeneity. Concurrently, atomistic simulations suggest the emergence of locally densely‐packed regions (LDPRs) with characteristically low activation energy for shear transformation. These findings indicate that plasticity can be sustained by heterogeneous structures wherein densely‐packed motifs, alongside conventional loosely‐packed regions, serve as potential shear transformation sites. This shifts the design paradigm from merely introducing LLPRs to strategically engineering heterogeneous structures that enable compensatory plasticity.