Corrosion of Aluminium Aerospace Alloys

The Junkers F13 airplane, which began production in 1919, was the first plane to be built using aluminum aerospace alloys. Nearly 100 years later, approximately 1,800 new planes are being built each year with aluminum aerospace alloys. For the five trillion or so dollars worth of existing aging airplanes, cost of aerospace corrosion in United States alone is an estimated 23 billion dollars per year. In addition, hidden corrosion costs have contributed to a bigger impact in the commercial aircraft industry. In 1988, in the corrosion sensitive environment of the Hawaiian islands, an Aloha Airlines 737 aircraft suffered an in-flight failure due to crevice corrosion in the lap joint of the fuselage. After this event, the aviation technical community launched a new era of advanced technology, improved procedures and higher standards for maintaining the world’s aging and corroding aircraft. This paper discusses types of corrosion that affect aluminum aerospace alloys including crevice corrosion, pitting, exfoliation, intergranular, stress corrosion cracking (SCC) and corrosion fatigue. Standardized testing to determine if the alloy is susceptible to these types of corrosion is explained and examples of how to mitigate certain types of corrosion is discussed.