|About this Abstract
|2022 TMS Annual Meeting & Exhibition
|Environmentally Assisted Cracking: Theory and Practice
|Effects of Atmospheric Corrosion on Corrosion Fatigue of AA7085-T7451: Investigating the Role of Surface Salts, Varied Humidity, and Temperature
|Brandon T. Free, Jason Niebuhr, Nathan Houser, Sarah Galyon Dorman, Jenifer (Warner) Locke
|On-Site Speaker (Planned)
|Brandon T. Free
Corrosion fatigue (CF) of 7xxx series aluminum alloys has been studied extensively in standardized environments including pure water vapor and full immersion in aqueous solutions. Despite this, the effects of atmospheric environments consisting of salt deposits that yield surface electrolyte have not been widely examined. The objectives of this work are to quantify the effects of surface electrolyte droplets, humidity, and temperature on CF crack growth rates (da/dN) in AA7085-T7451. To date, testing has shown that da/dN measured in 0.06 M NaCl is similar to that measured with 50 - 300 μg/cm2 NaCl on the surface and exposed to 80% RH air. Additional testing has examined the hysteresis associated with changing humidity above and below the deliquescent point for NaCl, showing that humidity ramp rate and time of wetness/dryness may be important for understanding atmospheric CF. Testing is ongoing to examine the effect of temperatures between -40 to 25 C.