Structural origin of deformation and dynamical heterogeneity in metallic glasses

ZY Yang and LH Dai, PHYSICAL REVIEW MATERIALS, 7, 113601 (2023).

DOI: 10.1103/PhysRevMaterials.7.113601

Heterogeneity in the deformation field, especially in the form of shear bands, is a universal feature in disordered solids. The current paradigm presents the deformation heterogeneity as the result of structural inhomogeneity which is controlled by the concentration of atomic ordering clusters or flow defects. Here, we show that, in contrast to the population of atomic clusters, their topology, i.e., spatial distribution, is the root cause of the strain localization. This conclusion is reached via a decoupling tactic which completely eliminates the effect of concentration. Under loading stimuli, model glasses with identical concentration but various topological connectivity of atomic ordering clusters show remarkably distinct mechanical behaviors. Deformation heterogeneity and shear banding emergence are linked to glasses with strong topological connectivity. Topological connectivity can be not only characterized as the structural origin of strain localization, but is also transferable to detect the dynamical heterogeneity. These results are instrumental to rationalize the emergence of shear bands in disordered solids in terms of the pure structural information.

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