| About this Abstract |
| Meeting |
Materials Science & Technology 2010
|
| Symposium
|
High Strain Rate Behaviors of Composites and Heterogeneous Materials: Experiments, Modeling, and Simulation
|
| Presentation Title |
A Density Functional Theory Study on Boundaries and Interfaces in Ultrafine-grained Aluminum Composites
|
| Author(s) |
Kaka Ma, Enrique Lavernia, Julie M Schoenung |
| On-Site Speaker (Planned) |
Kaka Ma |
| Abstract Scope |
In ultrafine-grained (UFG) aluminum composites developed by cryomilling and consolidation, segregation of N, O, and Mg is often observed at grain boundaries or at the matrix/reinforcement interfaces. The adsorption of N in the Al lattice leads to the formation of intermediate Al-N transition structures and eventually true aluminum nitride, which contributes to improvement in strength and may be influenced by the presence of Mg and O in close proximity to the reinforcement particles. Additionally, segregation of Mg at grain boundaries results in the formation of Mg-Al intermetallic phases that can also affect strength. In an effort to provide a fundamental understanding of these empirical observations, atomic models of the grain boundaries and interfaces in the composites are built using Materials StudioŽ. The optimal geometries, surface and interface energies, and the behavior of alloying elements and impurities at the boundaries and interfaces are investigated using first-principle density functional theory. |
| Proceedings Inclusion? |
Definite: A CD-only volume |