Shear banding behavior of metallic glasses (MGs) strongly correlates with the microstructural heterogeneity. Understanding how the nucleation and propagation of shear bands governed by the nanoscale structural heterogeneity are crucial for designing high-performance MGs. Herein, we utilized conventional Molecular dynamics (MD) and swap Monte Carlo (SMC) simulations to construct two phases of CuZr metallic glasses: one the soft phase with a high cooling rate about 1013 K/s, and the other one the hard phase with a extremely low cooling rate in simulations about 104 K/s. The soft phase is more prone to the plastic deformation due to the poor population of icosahedral clusters; the hard phase is of more icosahedral clusters, promoting shear localization once the shear bands form inside. We found a ductileto-brittle transition in the soft-and-hard phase ordered MGs with the increment of the hard-region fraction c. Additionally, the strategy of how to order these two phases could strongly affect the mechanical behavior of MGs. Dispersive and isolated hard-regions can enhance the mechanical stability of MGs, delaying the occurrence of shear banding. Instead, surrounding soft regions by hard regions can induce a secondary shear band that formed through the reorientation of plastic zones under constrained deformation, leading to a relatively more delocalized plastic deformation zones. The work unveils that the structural heterogeneity achieved by tuning the topology of soft and hard phase can significantly change the mechanical performance of MGs, and this could guide the design of metallic glasses with controllable structures via architectural ordering strategies.
Shoucheng et al. (Wed,) studied this question.