Abstract
Controlling shear band propagation is the key to obtain ductile metallic glasses. Here, we use a residual stress field to vary the direction of shear band propagation. We ascribe this behavior to the effect of the stress field on the activation of shear transformation zones (STZs) along their characteristic direction and we quantify this contribution to the energy of the process. Because of the progressively adverse orientation of the stress field, the energy stored as shear in the STZ decreases to a level where shear band propagation at alternative angles becomes energetically more favorable.
Highlights
Plastic deformation of bulk metallic glasses (BMGs) at room temperature occurs through the generation of highly localized shear bands propagating at the microscale in an approximately straight manner [1,2]
The magnitude of the stresses obtained from the finite-element method (FEM) simulations [Fig. 3(b)] is overall lower compared to the High-energy x-ray diffraction (HEXRD) results, the stress fields are very similar, supporting that the experimental data in Fig. 3(a) represent well the stresses generated by flash annealing
Room-temperature compression tests reveal that the flashannealed specimens yield at lower stress, subsequently work harden, and show a four times larger plastic strain than the as-cast BMG
Summary
Plastic deformation of bulk metallic glasses (BMGs) at room temperature occurs through the generation of highly localized shear bands propagating at the microscale in an approximately straight manner [1,2] ( shear band deflections have been observed at the nanoscale [3,4]). Distortion of each STZ is identical along the nascent shear band, determining the relatively straight trajectory of the band while it spans the entire specimen [1] If this is true, it would be possible to control the shear band path and the overall plastic deformation of BMGs by manipulating the orientation of STZ activation. Flash annealing represents a unique tool for introducing elastic stress fields into BMGs while avoiding the formation of shear bands [9] as, in contrast, occurs for shot-peened, cold-rolled, or imprinted BMGs [13,14,15,16,17] This permits us to use the trajectory of shear bands as a local probe in order to study the influence of stress fields on the underlying STZ activation mechanism without the interference resulting from the stress fields generated by preexisting bands [8].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
