The structure of shear bands in metallic glasses

Shear-band arrest and stress overshoots during inhomogeneous flow in a metallic glass

“…14 Another route intensely explored is investigating the underlying physics on how plastic flow develops at the microstructural or atomic scale, [5][6][7]15 which, however, entails severe experimental accessibility complications due to flow's confinement to the nmlength scale and rapid shear-band propagation during serrated flow that occurs within milliseconds at ambient temperature. 10,11,16 Nevertheless, specialized experimental techniques applied after deformation suggest that the deforming material within a shear band undergoes a structural change towards lower density, 17,18 being analogous to shear-induced dilation processes known to occur in a wide range of disordered or granular media. 19,20 This naturally emerges towards a picture in which the material in an active shear band is believed to be in a state of lower viscosity relative to the surrounding bulk matrix.…”

Nanoscale periodic corrugation to dimple transition due to “beat” in a bulk metallic glass

“…Below the glass-transition temperature, BMGs usually suffer a strong tendency for shear localization into ca. 10 nm thick shear bands [7][8][9][10][11][12][13] and undergo macroscopic brittle fracture [14][15][16][17]. However, there is clear evidence on the final fracture surfaces that BMGs are capable of legitimate plastic flow at the microscale [18][19][20].…”

Rate-dependent serrated flow and plastic deformation in Ti45Zr16Be20Cu10Ni9bulk amorphous alloy during nanoindentation

“…The thickness of the shear band can be estimated from figure 4(c) as ∼17 nm. This value is in the range of the typical thicknesses of shear bands (10-20 nm) in glass [46][47][48][49][50][51]. On the other hand, the strain increment in the band can be measured directly from the p-h curve ( figure 3(b)), assuming that the strain originates only from the serrated displacement.…”