Structural relaxation affecting shear transformation avalanches in metallic glasses

Abstract

Avalanche behaviors, characterized by power-law statistics and structural relaxation that induces shear localization in amorphous plasticity, play an essential role in deciding the mechanical properties of amorphous metallic solids (i.e., metallic glasses). However, their interdependence is still not fully understood. To investigate the influence of structural relaxation on elementary avalanche behavior, we perform molecular-dynamics simulations for the shear deformation test of metallic glasses using two typical metallic-glass models comprising a less-relaxed (as-quenched) glass and a well-relaxed (well-aged) glass exhibiting a relatively homogeneous deformation and a shear-band-like heterogeneous deformation, respectively. The data on elementary avalanches obtained from both glass models follow the same power-law statistics with different maximum event sizes, and the well-relaxed glass shows shear localization. Evaluating the spatial correlation functions of the nonaffine squared displacements of atoms during each elementary avalanche event, we observe that the shapes of the elementary avalanche regions in the well-relaxed glasses tend to be anisotropic, whereas those in the less-relaxed glasses are relatively isotropic. Furthermore, we demonstrate that a temporal clustering in the direction of the avalanche propagation emerges, and a considerable correlation between the anisotropy and avalanche size exists in the well-relaxed glass model.

arXiv comment11 pages, 9 figures

References in corpus (12)

• Dynamics of Viscoplastic Deformation in Amorphous Solids
• Intermittent dislocation flow in viscoplastic deformation
• Deformation and Failure of Amorphous Solidlike Materials
• Subextensive Scaling in the Athermal, Quasistatic Limit of Amorphous Matter in Plastic Shear Flow
• Bulk Metallic Glasses Deform via Slip Avalanches
• Evaluation of the "disorder temperature" and "free volume" formalisms via simulations of shear banding in amorphous solids
• Avalanches in Strained Amorphous Solids: Does Inertia Destroy Critical Behavior?
• The effect of inertia on sheared disordered solids: Critical scaling of avalanches in two and three dimensions
• Avalanches and Plastic Flow in Crystal Plasticity: An Overview
• Common dependence on stress for the statistics of granular avalanches and earthquakes
• Strain-rate and temperature-driven transition in the shear transformation zone for two-dimensional amorphous solids
• Barrier effect of grain boundaries on the avalanche propagation of polycrystalline plasticity

Cited by in corpus (2)

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