Structural perspectives on the elastic and mechanical properties of metallic glasses

Abstract

Articles you may be interested inUnderstanding the correlations between Poisson's ratio and plasticity based on microscopic flow units in metallic glasses Low beryllium content Zr-based bulk metallic glass composite with plasticity and work hardenability J. Appl. Phys. 115, 043519 (2014); 10.1063/1.4863454 Symmetry breaking and other nonlinear elastic responses of metallic glasses subject to uniaxial loading

The fracture of bulk metallic glasses

“…Rapid quenching can freeze the large scale and slow primary relaxation (the so-called the a-relaxation), while the fast secondary beta-relaxation, which is a reversible process, can be kept in the glass state, [77,84,85]. The microstructural origin of b-relaxation in metallic glasses is associated with the motion of groups of loose atoms in nano-scale localized soft regions of metallic glasses [87b,88], which is reminiscent of potential STZs or flow units in BMGs, because in simple atomic BMGs, no complicated mobility forms such as the intramolecular effect in other non-metallic glasses exist.…”

“…Compared with the elastic matrix, the defects of flow units are a group of atoms exhibiting a lower packing density, higher atomic mobility, higher energy dissipation rate, lower modulus, and higher energy states in the energy landscape [77][78][79][80][81][82][83][84][85]88]. The flow units show a collective rearrangement process during stress or thermal induced deformation.…”

“…(which act as the viscous flow units for deformation and glass transition) embodied in the elastic solid matrix, that is: metallic glass = ideal elastic glassy matrix + flow units [65,66,68,[79][80][81][82][83][84][85][86][87]. Compared with the elastic matrix, the defects of flow units are a group of atoms exhibiting a lower packing density, higher atomic mobility, higher energy dissipation rate, lower modulus, and higher energy states in the energy landscape [77][78][79][80][81][82][83][84][85]88].…”

The role of time in activation of flow units in metallic glasses

“…The strain rate dependent E of MGs, which make MGs behave hardening or softening, is attributed to the increase of fraction of the flow units at a lower strain rate or a longer activation time in MGs, because the MG with more liquid like regions shows larger softening behaviors [21]. The isothermal annealing far below T g , which can induce annihilation of the flow units, also leads to significant increase of E or stiffer of MGs [32]. As shown in Fig.…”

The Development of Structure Model in Metallic Glasses

“…Flow unit model is shown in Figure 11. In this model, they thought that the flow units as liquid-like quasi phases were embedded in solid-like glassy substrate 122,123 .…”