| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Nanostructured Materials in Extreme Environments II
|
| Presentation Title |
Dominant High-temperature Mechanism for Grain Size Stability in Nanocrystalline Alloys |
| Author(s) |
Mostafa Saber |
| On-Site Speaker (Planned) |
Mostafa Saber |
| Abstract Scope |
In Nanocrystalline metals, the nano-scale microstructure and its exceptional properties are inherently unstable at elevated temperatures. Solute additions crucially contribute to stabilizing the nano-grains by mitigating the grain boundaries movement. This is mainly caused by pinning the grain boundary mobility (kinetic mechanism) or by solute segregation toward the grain boundary (thermodynamic mechanism). The kinetic stabilization is temperature-dependent and will become ineffective at elevated temperatures and longer times. In contrast, the thermodynamic approach governs long-term stability because the energy required to grain growth is diminished. It is confirmed that atomic oxygen is extensively diffused from the particle surface into the microstructure under the non-equilibrium process of ball milling. This impurity leads to oxide formation during a high-temperature treatment and provides a secondary contributor to the thermal stability beside the solute segregation effect. Our results explored the dominant mechanism in grain size stabilization. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
High-Temperature Materials, Phase Transformations, Modeling and Simulation |