2, Lawrence Berkeley National Laboratory, Berkeley, California, United States
The effects of structural and spatial heterogeneity on the deformation behaviors of metallic glass are investigated by a mesoscale shear transformation zone dynamics model. The structural heterogeneity is captured by a Gaussian distribution of shear moduli for shear transformation zones, which is informed by molecular dynamics simulations. The spatial heterogeneity is tuned by achieving an exponential decay correlation function of shear moduli with a specific correlation length. We identify a critical spatial correlation length of the shear moduli. Below the critical length, the formation of shear bands is stress-dictated, signified by a stress overshoot on the stress-strain responses. Above the critical length, the formation of shear bands is controlled by the percolation of elastically soft regions in the heterogeneous glassy structure and after yielding a perfect plastic flow is observed. At the critical correlation length, the simulated glass exhibits the largest strain-to-failure value with the least strain localization propensity.