Abstract

Metallic glasses possess outstanding mechanical properties, including high yield strength, large elastic limits, and excellent fracture toughness, positioning them as promising materials for applications in load-bearing structures, sports equipment, and beyond. However, their brittle fracture behavior, characterized by localized shear band instability, remains a critical challenge. The lack of crystalline structures and well-defined defects in metallic glasses complicates the understanding of the underlying mechanisms responsible for such behavior. This talk presents a comprehensive investigation into the deformation mechanisms of metallic glasses. A thermodynamically consistent continuum model is developed to capture viscoplastic deformation and the evolution of spatial heterogeneity. The model, which correlates local viscoplastic strain rates with the atomic flux gradient tensor, is implemented in the open-source finite element platform FEniCS. It successfully reproduces key deformation phenomena, including shear band localization, creep, and cavitation under diverse loading conditions. Additionally, laser shock experiments were performed to examine the fracture behavior of metallic glasses under ultrahigh strain rates (>10⁷ s⁻¹). Cu₅₀Zr₅₀ metallic glass ribbons demonstrated near-ideal fracture strengths, surpassing those of crystalline metals under similar conditions. The talk will also discuss void growth kinetics during tension, shedding light on the fracture processes of metallic glasses at extreme strain rates.