Schwarz, Udo. 2025. « Mechanisms of nanoscale deformation in bulk metallic glasses investigated using pillar compression ». Communication lors de la conférence : CSME-CFDSC-CSR 2025 International Congress (Montreal, QC, Canada, May 25-28, 2025).
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Résumé
Metallic glasses accommodate most of their macroscopic plastic deformation through the activation of shear bands. These shear bands, however, first need to form before they can get activated, and the mechanisms of how this happens are still researched. To help fill this gap, we systematically investigated the deformation behavior of Pt57.5Cu14.7Ni5.3P22.5 metallic glass under micro-/nanopillar compression, where pillars were prepared using a novel method based on thermoplastic forming. This manufacturing method not only produces better-defined pillar geometries with lesser structural flaws that previous methods yielded, but it also enables the fabrication of a large number of identical pillars. At higher strain rates, local yielding happens in the areas featuring the biggest flaws due to a lack of time to properly accommodate the external pressure, which causes the distribution of yield loads to become more scattered. Interestingly, fracture stress exhibited a different pattern, showing no significant strain rate sensitivity. Additionally, annealed pillars displayed more closely clustered fracture loads, consistent with the understanding that annealing-induced structural relaxation enhances atomic packing, reduces defects, and increases resistance to compression. Overall, the findings suggest a three-phase deformation mechanism, where the pillars first deform elastically until plastic deformation starts in less dense areas of the pillar. This plastic deformation evolves in a combination of smooth, continuous flow alternating with abrupt, larger-scale atomic reordering, where the abrupt reordering processes continuously increase in size. Finally, shear bands form that cover the entire width of the pillar, which ultimately leads to its collapse.
| Type de document: | Communication (Communication) |
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| Informations complémentaires: | Progress in Canadian Mechanical Engineering, Volume 8. Co-chairs: Lucas A. Hof, Giuseppe Di Labbio, Antoine Tahan, Marlène Sanjosé, Sébastien Lalonde and Nicole R. Demarquette. |
| Date de dépôt: | 18 déc. 2025 14:39 |
| Dernière modification: | 18 déc. 2025 14:39 |
| URI: | https://espace2.etsmtl.ca/id/eprint/32176 |
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