TY - JOUR A1 - Das, A. A1 - Dufresne, E.M. A1 - Maaß, Robert T1 - Structural dynamics and rejuvenation during cryogenic cycling in a Zr-based metallic glass T2 - Acta Materialia N2 - Subjecting metallic glasses repeatedly to liquid nitrogen temperature has become a popular method to homogeneously rejuvenate the material. Here we reveal the atomic-scale structural dynamics using in- situ x-ray photon correlation spectroscopy (XPCS) during and after cryogenic cycling of a Zr-based metallic glass in two structural states (plate and ribbon). Heterogeneous structural dynamics is observed at 300 K that changes to monotonic aging at 78 K. It is found that cryogenic cycling homogenizes the relaxation time distribution. This effect is much more pronounced in the ribbon, which is the only structural state that rejuvenates upon cycling. We furthermore reveal how fast atomic-scale dynamics is correlated with longtime structural relaxation times irrespective of the structural state, and that the ribbon exhibits unexpected additional fast atomic-scale relaxation in comparison to the plate material. A structural picture emerges that points towards heterogeneities in the fictive temperature as a requirement for cryogenic energy storage. PB - Elsevier Ltd. KW - Structural dynamics KW - Metallic glass KW - Relaxation KW - Rejuvenation KW - Cryogenic cycling PY - 2020 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/51311 AN - OPUS4-51311 SN - 1359-6454 VL - 196 SP - 723 EP - 732 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany