Structure-dynamics relationships in cryogenically deformed bulk metallic glass

Florian Spieckermann, Daniel Şopu, Viktor Soprunyuk, Michael B. Kerber, Jozef Bednarčík, Alexander Schökel, Amir Rezvan, Sergey Ketov, Baran Sarac, Erhard Schafler, Jürgen Eckert

The atomistic mechanisms occurring during the processes of aging and rejuvenation in glassy materials involve very small structural rearrangements that are extremely difficult to capture experimentally. Here we use in-situ X-ray diffraction to investigate the structural rearrangements during annealing from 77 K up to the crystallization temperature in Cu44Zr44Al8Hf2Co2 bulk metallic glass rejuvenated by high pressure torsion performed at cryogenic temperatures and at room temperature. Using a measure of the configurational entropy calculated from the X-ray pair correlation function, the structural footprint of the deformation-induced rejuvenation in bulk metallic glass is revealed. With synchrotron radiation, temperature and time resolutions comparable to calorimetric experiments are possible. This opens hitherto unavailable experimental possibilities allowing to unambiguously correlate changes in atomic configuration and structure to calorimetrically observed signals and can attribute those to changes of the dynamic and vibrational relaxations (α-, β- and γ-transition) in glassy materials. The results suggest that the structural footprint of the β-transition is related to entropic relaxation with characteristics of a first-order transition. Dynamic mechanical analysis data shows that in the range of the β-transition, non-reversible structural rearrangements are preferentially activated. The low-temperature γ-transition is mostly triggering reversible deformations and shows a change of slope in the entropic footprint suggesting second-order characteristics.

Physics of Functional Materials, Nanomagnetism and Magnonics, Dynamics of Condensed Systems
External organisation(s)
Montanuniversität Leoben, Österreichische Akademie der Wissenschaften (ÖAW), Technische Universität Darmstadt, Deutsches Elektronen-Synchrotron DESY, Pavol Jozef Šafárik University in Košice
Nature Communications
Publication date
Peer reviewed
Austrian Fields of Science 2012
103018 Materials physics
ASJC Scopus subject areas
Chemistry(all), Biochemistry, Genetics and Molecular Biology(all), Physics and Astronomy(all)
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