About this Abstract |
| Meeting |
MS&T26: Materials Science & Technology
|
| Symposium
|
Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
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| Presentation Title |
Coupled Evolution of Grain Boundaries and Precipitate-Matrix Interfaces in Aluminum Alloys Under Pulse-Heated Dynamic Loading |
| Author(s) |
Adam J. Seigler, Steven P. Mates, Hang Z. Yu |
| On-Site Speaker (Planned) |
Adam J. Seigler |
| Abstract Scope |
The dynamic mechanical response of aerospace aluminum AA7075 is governed by the coupled evolution of three microstructural families: η'/η precipitate–matrix interfaces, the dislocation substructure they interact with via shearing or Orowan looping, and dislocation–grain boundary interactions. Using a rapid pulse-heated Kolsky bar, we measure the high-strain-rate (10^3–10^4 s-1) response across T6, T73, and solid-solution tempers over 300–673 K under rapid adiabatic heating. From the temperature-dependent flow stress, we extract a phenomenological JMAK dissolution kinetics framework fit to mechanical stress evolution — rather than direct calorimetry — quantifying precipitate dissolution during dynamic loading. Complementary USAXS/SAXS and post-mortem EBSD reveal temper-distinct subgrain architectures and LAGB/HAGB fractions reflecting precipitate–boundary interactions, including grain boundary η films and precipitate-free zones. Above ~300 °C, progressive dissolution removes the precipitate population, driving convergence of grain boundary character and flow stress across tempers. |