| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Mechanical Response of Materials Investigated Through Novel In-Situ Experiments and Modeling
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| Presentation Title |
Strain Rate Dependence of Activation Volume in Au Ultrafine Grained Thin Films Investigated by In Situ TEM |
| Author(s) |
Yichen Yang, Kunqing Ding, Xing Liu, Ting Zhu, Josh Kacher, Olivier Pierron |
| On-Site Speaker (Planned) |
Yichen Yang |
| Abstract Scope |
We explore the strain rate-dependent plastic deformation mechanisms in free-standing ultrafine-grained Au thin films using in-situ Transmission Electron Microscopy (TEM) and advanced Micro Electro Mechanical System (MEMS) nanomechanical testing. This approach can capture true activation volume while directly observing active deformation mechanisms. Experiments were conducted across strain rates from ~10-5 to 10-1 s-1. Consistently, higher rates correlated with larger activation volumes, suggesting the competition between diffusive and displacive deformation mechanisms. In-situ TEM observations showed HSR activates multiple slip systems and formation of dislocation junctions, providing direct evidence that increasing strain rate leads to activation involving more displacive deformation mechanisms. Additionally, grain size effect on activation volume was analyzed with average grain size from 142 to 287 and 768 nm, with larger grain sizes correspond to higher activation volumes. This study marks the first in-situ TEM observations of strain rate effect on UFG materials coupled with true activation volume measurement. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Mechanical Properties, Thin Films and Interfaces, Nanotechnology |