Intrinsic heterogeneity of shear banding: hints from diffusion and relaxation measurements of Co micro-alloyed PdNiP-based glass
R. Hubek, M. Seleznev, I. Binkowski, M. Peterlechner, S. V. Divinski, G. Wilde.
Journal of Applied Physics, AIP Publisher, New York, 127, 115109, (2020)
The influence of Co micro-alloying (1 at. %) on the shear band diffusion and the relaxation processes in a model PdNiP bulk metallic glass is investigated. The shear bands are induced by one-pass cold-rolling. In addition to a fast shear band diffusion branch (Dsb≃10−16m2/s at 473 K), with the diffusivity being similar to that observed for the cold-rolled standard Pd40Ni40P20 composition, an ultrafast diffusion branch (Dsb≃10−14m2/s at the same temperature) is found to exist in the micro-alloyed glass. Combined with previously reported observations of faster relaxation of both the Boson peak height and the fictive temperature, the results indicate that Co micro-alloying affects the excess free volume distribution and thus changes the potential energy landscape of the glass, introducing a higher number of local atomic arrangements prone to the formation of shear transformation zones under plastic deformation.