| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Environmentally Assisted Cracking: Theory and Practice
|
| Presentation Title |
Using In Situ Crack Tip pH Measurements to Understand the Corrosion Fatigue Susceptibility in 2xxx (Al-Cu) and 7xxx (Al-Zn) Al Alloys |
| Author(s) |
Gabby C. Montiel, Jenifer Locke |
| On-Site Speaker (Planned) |
Gabby C. Montiel |
| Abstract Scope |
This research aims to quantify corrosion fatigue (CF) susceptibility differences between 2xxx and 7xxx Al alloys by varying copper and zinc content to gain insight into role of corroding Cu-containing strengthening precipitates. Crack tip pH is measured in situ as a function of alloy type and loading conditions. Results to date show that under freely corroding conditions in 0.6M NaCl loaded at R of 0.6, ∆K of 6 MPa√m, and f of 0.1 Hz, AA7075-T76 has a slightly acidic crack tip, while AA2024-T8 shows an alkaline crack tip pH. Results are consistent with hypothesis that AA2xxx shows more resistance to CF because localized corrosion of crack wake facilitates Cu replating increasing crack cathodic reactions kinetics, which mitigates acidic crack tip development allowing passivity at the crack tip to inhibit CF. Continued research is underway to look at compositions varying Cu and Zn and link their corrosion, repassivation, and CF behavior. |
| Proceedings Inclusion? |
Planned: |