Control Shear Banding in Metallic Glasses to Enable Tensile Ductility: A Brief Review

Metallic glasses (MGs) exhibit excellent mechanical properties, yet their poor tensile ductility greatly limits their practical applications as structural and functional materials. Shear banding is a typical localized rheological deformation behavior inherent to amorphous materials, which stems from heterogeneous atomic rearrangement and regional viscosity fluctuations in the glassy matrix, and fundamentally determines the macroscopic mechanical properties of MGs and their composites. This review discusses the relationship between typical toughening strategies and shear banding behavior, and proposes that deliberate suppression of shear band (SB) initiation or deceleration of their rapid propagation can effectively promote distributed plastic flow. In this review, nanosizing and metamaterial strategies are shown to hinder the formation of mature SBs, while metallic glass matrix composites (MGMCs), nanoglasses (NGs), notched design, and rejuvenation treatments contribute to restraining SB propagation. Current approaches have successfully regulated shear banding behavior and thereby realized appreciable tensile ductility in MGs. Novel design and fabrication techniques for amorphous alloys, which suppress SB initiation and retard SB propagation to achieve homogeneous plastic flow, open up new avenues for realizing controllable plasticity of MGs.