Abstract
Accelerated corrosion testing is an important tool for understanding the corrosion behavior of aerospace alloys, but many standardized accelerated tests do not correlate well with seacoast exposures, and results can be drastically different from test-to-test. Previous testing of aluminum lithium alloy 2060 has shown that DB ASTM G85-A2 correctly distinguishes between exfoliation susceptible and resistant tempers. In the current study, in-situ measurements were used to deconstruct the testing environment of DB ASTM G85-A2 to provide an understanding of what makes this test successful when others are not. Time of wetness measurements showed that complete drying of the sensor did not occur until 1.5 – 4 hours after the dry air purge began. After 2 days, the open circuit potential of AA2060 was stable during the salt spray cycle and decreased during the dry cycle. After longer testing time (8 days), the potential was lower, due to activation of more localized corrosion sites. In addition, a peak in potential was observed at around 10 minutes into the dry air purge after 8 days of testing. This change in potential was attributed to the impact of relative humidity on electrolyte film thickness and cathodic kinetics.
