TY - JOUR

T1 - Structure-dynamics relationships in cryogenically deformed bulk metallic glass

AU - Spieckermann, Florian

AU - Şopu, Daniel

AU - Soprunyuk, Viktor

AU - Kerber, Michael Bernhard

AU - Bednarčík, Jozef

AU - Schökel, Alexander

AU - Rezvan, Amir

AU - Ketov, Sergey

AU - Sarac, Baran

AU - Schafler, Erhard

AU - Eckert, Jürgen

N1 - Publisher Copyright: © 2022, The Author(s).

PY - 2022/1/10

Y1 - 2022/1/10

N2 - 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.

AB - 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.

UR - https://doi.org/10.1038/s41467-021-27661-2

U2 - 10.1038/s41467-021-27661-2

DO - 10.1038/s41467-021-27661-2

M3 - Article

VL - 13.2022

JO - Nature Communications

JF - Nature Communications

SN - 2041-1723

IS - 1

M1 - 127

ER -