| About this Abstract |
| Meeting |
2022 TMS Annual Meeting & Exhibition
|
| Symposium
|
Grain Boundaries and Interfaces: Metastability, Disorder, and Non-Equilibrium Behavior
|
| Presentation Title |
Disconnection-mediated Transition in Segregation Structure at Twin Boundaries: A Molecular Dynamic Simulation of Platinum-gold System |
| Author(s) |
Chongze Hu, Douglas Medlin, Remi Dingreville |
| On-Site Speaker (Planned) |
Chongze Hu |
| Abstract Scope |
Twin boundaries can significantly control the stability and mechanical properties of many nanocrystalline materials. Thus, understanding their atomic-level structure and chemistry is important to optimize fabrication recipes for improving the properties of nanocrystalline materials. In this talk, we will discuss a novel grain boundary transition in segregation structure driven by the disconnection (i.e., step plus dislocation) in gold-decorated platinum twin boundaries. By performing first-principles calculations and molecular dynamic simulations, we show that gold segregation can transition from alternating bilayer structure to trilayer segregation-only structure when the disconnection contains the stacking fault in twin boundary. Such a behavior has been observed for various faulted disconnections with different heights and dislocation features. We further demonstrate that this transition can be explained by the local pressure drop and increasing of segregation volume across the stacking faults, which is also supported by classical Langmuir-Mclean isotherms. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Modeling and Simulation, Phase Transformations, Other |