| About this Abstract |
| Meeting |
MS&T24: Materials Science & Technology
|
| Symposium
|
Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
|
| Presentation Title |
In Situ TEM Strain Rate Dependence of Activation Volume in Au Ultrafine Grained Thin Films |
| Author(s) |
Yichen Yang, Kunqing Ding, Ting Zhu, Josh Kacher, Olivier N. Pierron |
| On-Site Speaker (Planned) |
Yichen Yang |
| Abstract Scope |
The effect of applied strain rate (from ~10^-5 to 10^-1 /s) on true activation volume is investigated in free-standing ultrafine grained Au thin films using in situ TEM MEMS-based nanomechanical testing. The in situ TEM experiments are employed to identify plastic deformation mechanisms, obtain key details, and measure the sample-level true activation volume. In addition to activation volume measurements, in situ TEM monotonic experiments are performed to quantify the strain rate sensitivity to the 0.2% offset yield stress. The activation of relevant GB mediated dislocation mechanisms is also modeled using the atomistic free-end nudged elastic band (FENEB) method as a function of representative, experimentally observed GB characters and local stress. These results are used to study the competition between displacive and diffusive GB mechanisms in small-grained metals, thanks to a model of grain-size-dependent activation volume. |