Plastic deformation and failure mechanisms in nano-scale notched metallic glass specimens under tensile loading

Deformation Behavior of Bulk Metallic Glasses and High Entropy Alloys under Complex Stress Fields: A Review

“…The authors would like to point out that at sub-micron scales, the formation of localized shear bands can also be suppressed till fracture due to the change of deformation modes [65]. This phenomenon has also been observed in notched MG specimens with sub-micron sizes, where the change of notch sizes can tune the deformation modes from localized shear-banding to homogeneous softening and necking [61][62][63]. A summary on the homogeneous deformation behavior of BMGs under complex stress fields will be given in Section 5 in this paper, and thus not described in detail here.…”

“…Pan et al [ 123 ] have investigated the physical origin of the homogenous deformation, and found that voids and cavitations were initiated at the notch root when the stress triaxiality exceeds a critical value. On the other hand, Dutta et al [ 62 ] have also observed the transition of deformation modes from shear-banding ( Figure 10 a,b) to homogeneous deformation with necking ( Figure 10 c,d). With a relatively sharper notch ( Figure 10 c), plastic zones first initiated from the notch root due to stress concentrations, and then evolved to incipient shear bands ( Figure 10 d).…”

“…As shown in Figure 1 , the notches can serve as stress concentrators to facilitate the localization of plastic zones, leading to the initiation of shear bands. Following studies have examined the effect of notch geometries and sizes on the formation of shear bands [ 61 , 62 , 63 ]. They have shown that the initiation of shear bands can be tailored by introducing notches with appropriate geometries and sizes, which can serve as stress concentrators for highly localized shear strains.…”

“… MD simulation results of the Mises strain plots of unnotched ( a ) and notched ( b – f ) specimens, where ( c – f ) shows the evolution of plastic zones in a specimen with a sharper notch than ( b ). Adapted from [ 62 ] with permission of Elsevier. …”

Normal stress effect on plastic yielding of notched metallic glass: a finite element simulation study

“…Notched metallic glass have abstracted many interest because the global plasticity of metallic glass specimens could definitely improve, including normal and nano scale sample (Sha et al 2015, Yang et al 2017, Dutta et al 2018, and several methods, such as slipline field theory, finite element analysis (FE) and Neuber's stress analysis, etc, have also been applied to reveal the effects of notch (Qu et al 2014). However there are more attention paid on the effects of notches shape and sharpness, little care on the slope of the notch (Henann and Anand 2009, Sha et al 2015, Chen et al 2016, Gu et al 2017, but with different slope, there may exhibit different deformation and stress-strain state.…”