About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
|
| Symposium
|
Mechanical Behavior at the Nanoscale VIII
|
| Presentation Title |
Pathway-Dependent Drivers of Abnormal Grain Growth in Nanocrystalline Ni Thin Films Revealed by In-Situ TEM and EBSD |
| Author(s) |
Yichen Yang, Yazhuo Liu, Ting Zhu, Olivier Pierron, Josh Kacher |
| On-Site Speaker (Planned) |
Yichen Yang |
| Abstract Scope |
Abnormal grain growth (AGG) is a selective coarsening process in which a few grains grow abnormally large compared to the matrix. In nanocrystalline metallic thin films, AGG is widely associated with multiple driving forces, yet their relative importance remains context-dependent and often unresolved. Using MEMS-based in-situ 4D-STEM tensile and EBSD fatigue testing, the growth of more than 10,000 grains was tracked and analyzed statistically. We demonstrate that surface energy, size, and elastic strain energy can alternate as the primary AGG driver in the same material, depending on the imposed thermomechanical history. Annealing retained the classical surface-energy–driven AGG, producing a strong (111) fiber texture. During stress-relaxation at room temperature, however, the grains that coarsened most were simply the largest ones and therefore maintained the initial texture, with strain energy density being a secondary driving force. Under high cycle fatigue, growth favored orientations with lower elastic modulus along the loading axis. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, Other, Thin Films and Interfaces |