Structural signatures of primary and secondary relaxation during physical aging of a metallic glass
Abstract
Physical aging drives glasses toward equilibrium and changes their thermodynamic and mechanical properties, but the accompanying microscopic structural evolution remains poorly understood. Here, using our recently developed low-background setup combining fast scanning calorimetry with \emph{in-situ} X-ray total scattering, we investigate microscopic structural changes during physical aging in Pd42.5Cu30Ni7.5P20 metallic glass. The measurements span an unprecedented six orders of magnitude in time and a temperature range extending from above the glass transition temperature to more than 150\,K below it. We observe dominant structural changes near the first and second peaks of the structure factor. Near and above the glass transition temperature, changes in the first sharp diffraction peak closely follow enthalpy relaxation and are associated predominantly with increasing degrees of medium-range ordering. At lower temperatures, the enthalpy evolution can no longer be described by this contribution alone, revealing an additional, faster relaxation process that correlates with changes near the second diffraction peak and thus short-range structural rearrangements, including increased Pd--Pd correlations. These results establish a direct connection between thermodynamic relaxation and structural evolution, providing strong evidence that primary and secondary aging processes are associated with distinct structural length scales.
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BibTeX
@misc{baraldi2026structural,
title = {{Structural signatures of primary and secondary relaxation during physical aging of a metallic glass}},
author = {Beatrice Baraldi and Stefano Marchesin and Davide Marchesi and Lara Piemontese and Francesco Dallari and Søren S. Sørensen and Eloi Pineda and Marco Di Michiel and Giulio Monaco and Peihao Sun},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40298},
eprint = {2610.40298},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40298},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - UNPB
TI - Structural signatures of primary and secondary relaxation during physical aging of a metallic glass
AU - Beatrice Baraldi
AU - Stefano Marchesin
AU - Davide Marchesi
AU - Lara Piemontese
AU - Francesco Dallari
AU - Søren S. Sørensen
AU - Eloi Pineda
AU - Marco Di Michiel
AU - Giulio Monaco
AU - Peihao Sun
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40298
UR - https://arxiv.org/abs/2610.40298
AB - Physical aging drives glasses toward equilibrium and changes their thermodynamic and mechanical properties, but the accompanying microscopic structural evolution remains poorly understood. Here, using our recently developed low-background setup combining fast scanning calorimetry with \emph{in-situ} X-ray total scattering, we investigate microscopic structural changes during physical aging in Pd_42.5Cu_30Ni_7.5P_20 metallic glass. The measurements span an unprecedented six orders of magnitude in time and a temperature range extending from above the glass transition temperature to more than 150\,K below it. We observe dominant structural changes near the first and second peaks of the structure factor. Near and above the glass transition temperature, changes in the first sharp diffraction peak closely follow enthalpy relaxation and are associated predominantly with increasing degrees of medium-range ordering. At lower temperatures, the enthalpy evolution can no longer be described by this contribution alone, revealing an additional, faster relaxation process that correlates with changes near the second diffraction peak and thus short-range structural rearrangements, including increased Pd--Pd correlations. These results establish a direct connection between thermodynamic relaxation and structural evolution, providing strong evidence that primary and secondary aging processes are associated with distinct structural length scales.
ER -