Developement of reliable accelerated corrosion tests for aluminum alloys used in the aerospace industry

Abstract

Aluminum alloys are not immune to corrosion which can take the form of localized corrosion. Thus, the assessment of the corrosion behavior of aluminum alloys under atmospheric conditions is a major topic for the aerospace industry. One major difficulty in this task is the lack of robust and reliable accelerated corrosion test(s) in this field. Indeed, several tests as the Neutral Salt Spray test (ASTM B117) are used to assess the general corrosion resistance of aluminum, but these tests were not developed specifically for the aerospace industry and are not representative of service conditions. The aim of the present study was to compare the results of various accelerated corrosion tests conditions (ASTM B117, VDA 233-102, Volvo STD 423-0014) with newly developed test conditions. Hence different accelerated corrosion tests were designed by varying several parameters in the Volvo STD 423-0014 such as the salt concentration, the time of wetness and the relative humidity. The results obtained on 8 aluminum alloys (2xxx, 7xxx and Al-Li alloys) were then compared to marine exposures. From the results, one test provides the same type of corrosion attacks on the different alloys as under atmospheric exposures in the marine site and a good acceleration factor.