Hierarchical micro-nanostructured Zr-based metallic glass with tensile plasticity

Abstract

Metallic glasses (MGs) exhibit many unique properties because of their disordered microstructure. However, the absence of tensile plasticity at room temperature severely restricts the potential of MGs as high-performance structural materials. Here, Zr-based MG with a hierarchically heterogeneous structure in length was fabricated to enhance the tensile plasticity. Higher structural heterogeneity with a characteristic length of 12–20 nm was obtained by thermal cycling treatment. Subsequently, a micron array with a lower elastic modulus was prepared via high-frequency vibration. The hierarchical micro-nanostructured Zr-based MG exhibits a tensile plasticity of 0.68% at room temperature. Combined with finite element calculations and molecular dynamics simulations, the mechanism of the plastic deformation is attributed to more activated deformation units at the nanoscale and shear bands blocking and branching by complicated stress distributions at the micrometer scale. The findings presented herein can expand the understanding of structural heterogeneity, and provide a theoretical foundation for enhancing the tensile plasticity of MGs.