SYMPOSIA PAPER Published: 01 January 1982
STP33204S

Accelerated Atmospheric-Corrosion Testing

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No accurate methods are known for accelerated testing of corrosion which yield reliable results for predicting the service life of aircraft components and materials which degrade or fail due to environmental attack. In an effort to provide the basis for development of realistic accelerated corrosion tests, research is being conducted in controlled atmospheres on the localized environmental enhancement of crack-growth rates of aerospace alloys. Corrosion-fatigue and rising-load experiments have been conducted using accelerating pollutants such as sulfur dioxide (SO2) and ambient air to 100 percent relative humidity air in a specially designed atmospheric chamber. Initial results indicate that realistic environmental enhancement of crackgrowth rates can be employed to develop accelerated tests which can be related to actual in-service degradation. For materials with high stress-corrosion susceptibility, the threshold for crack growth (KIscc) was estimated to be 45 to 46 MPa √m for 4340 steel at a 1440-MPa yield strength level, as compared to 49 to 52 MPa √m as determined by means of rising-load test and 44 to 46 MPa √m by fracture analysis in 1000-ppm SO2 at 80 percent relative humidity. Thus, a rapid and reproducible method for KIscc determination appears feasible.

Author Information

Khobaib, M
Army Materials and Mechanics Research Center, Watertown, Mass.
Chang, FC
Army Materials and Mechanics Research Center, Watertown, Mass.
Keppler, EE
Army Materials and Mechanics Research Center, Watertown, Mass.
Lynch, CT
Air Force Wright Aeronatical Laboratories, Wright-Patterson Air Force Base, Ohio
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Details
Developed by Committee: G01
Pages: 374–394
DOI: 10.1520/STP33204S
ISBN-EB: 978-0-8031-4832-1
ISBN-13: 978-0-8031-0702-1