Origin of Ultrafast Ag Radiotracer Diffusion in Shear Bands of Deformed Bulk Metallic Glass Pd40Ni40P20

摘要

Measurements of Ag radiotracer diffusion in shear bands of deformed bulkmetallic glass, Pd40Ni40P20, [Joachim Bokeloh, Sergiy V. Divinski, GerritReglitz, and Gerhard Wilde, Phys. Rev. Lett. 107, 235503 (2011).] have found acolossal enhancement of diffusion coefficient by more than eight orders ofmagnitude than in undeformed Pd40Ni40P20. Suggestion was made by Bokeloh et al.that enhanced diffusion occurs in high-mobility pathways originating from someexcess free volume distribution inside the shear bands. Although plausible,this qualitative suggestion does not allow quantitative calculation of theenhancement. The impasse is avoided by using the Coupling Model to calculatethe maximum of the enhancement of diffusivity possible in high-mobilitypathways of the shear bands. Within the range of eight to ten orders ofmagnitude, the calculated maximum enhancement is capable to account for theexperimental observation.