About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
|
| Symposium
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Microstructural Control in Materials Processing: Role of Phase Transformation Pathways
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| Presentation Title |
Microstructural Control Strategies to Slow Sensitization Rates in 5XXX Series Aluminum Alloys |
| Author(s) |
Likun Sun, Gajanan Jayade, Matthew A. Steiner |
| On-Site Speaker (Planned) |
Matthew A. Steiner |
| Abstract Scope |
As super-saturated solid solutions of Al-Mg, 5XXX series aluminum alloys are susceptible to sensitization via intergranular precipitation of the anodic β-phase, which promotes intergranular corrosion, exfoliation and stress corrosion cracking in marine environments. Due to a slow bulk diffusion rate, the β-phase forms intergranularly following a series of fast diffusion mechanisms governed by microstructural features. Mg primarily reaches the boundaries via pipe diffusion along dislocation cores, then collects into existing precipitates near instantaneously in relative terms due to grain boundary diffusion, leading to a site-saturated nucleation behavior with a precipitate population set at very early sensitization stages. Results presented will demonstrate that introducing small amounts of initial sensitization at temperatures above typical environmental conditions can lead to long-lasting slower subsequent sensitization kinetics in these alloys that extend their service life by up to a factor of two, highlighting how small processing modifications can significantly impact phase transformation pathways. |