Spectrum Corrosion Fatigue Test of Various Aluminum Alloys. Phases I and II. RA-5C Extended Service Life Program.
ROCKWELL INTERNATIONAL COLUMBUS OH COLUMBUS DIV
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A primary purpose of this program was to study the behavior of 2020-T651 Aluminum Alloy plate specimens under adverse environmental conditions to evaluate the service life of RA-5C inner panel wing skins. Comparative evaluations were made also on 7075-T651, 7075-T73, 2024-T851 and 2024-T351 plate materials. Pre-fretted countersunk hole specimens were tested under a maneuver spectrum loading applied with a separate or combined 30-day 3-12 salt solution alternate immersion pre-exposure, or concurrent 3-12 salt solution or distilled water exposure while cycling. Limited tests were conducted with Alodine coating in the hole, with specimens made from wings of five year exposure, and with reworking of corroded and fatigue damaged holes to restore fatigue life. Simulated corrosive environments had a significant adverse effect on maneuver spectrum fatigue life for all five Aluminum Alloy plate materials tested. It is believed that the results are indicative of a reduction in fatigue life that can occur in service operation when fatigue-critical wing skin holes are not protected adequately. Author
- Patrol and Reconnaissance Aircraft
- Properties of Metals and Alloys