| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Environmentally Assisted Cracking: Theory and Practice
|
| Presentation Title |
Sensitization, Loading Frequency, and Electrochemical Potential Effects on Corrosion Fatigue Kinetics of AA5456-H116 |
| Author(s) |
David J. Schrock, Jenifer S. (Warner) Locke |
| On-Site Speaker (Planned) |
David J. Schrock |
| Abstract Scope |
5xxx series aluminum-magnesium alloys possess excellent corrosion resistance in the as-fabricated condition. However, alloys with greater than 3 wt.% Mg can become sensitized after sufficient exposure above 40 °C. Sensitization increases susceptibility to environment assisted cracking. In this work, effects of sensitization level (DoS), fatigue loading frequency (f), and electrochemical potential on AA5456-H116 corrosion fatigue kinetics (da/dN) in 3.5 wt.% NaCl are investigated. Results reveal an inverse relationship between da/dN and loading f in microstructures with DoS of 24 mg/cm2 or greater. At a singular low f (0.03 Hz), high DoS (65 mg/cm2) accelerates da/dN fivefold over microstructure in the as-fabricated condition. Microstructures having DoS of 22 mg/cm2 or less are unaffected by sensitization and have f-independent da/dN below 1 Hz. Cathodic polarization to −970 mVSCE, below β breakdown, reduces da/dN an order of magnitude below da/dN at OCP. Hypotheses regarding the source of the inverse f-dependence will be discussed. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |