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Aluminum-Lithium Light Weight Frangible Collar Development

Journal Article
ISSN: 1946-3855, e-ISSN: 1946-3901
Published September 16, 2008 by SAE International in United States
Aluminum-Lithium Light Weight Frangible Collar Development
Citation: Mulazimoglu, H., Pinheiro, R., and Haylock, L., "Aluminum-Lithium Light Weight Frangible Collar Development," SAE Int. J. Aerosp. 1(1):788-797, 2009,
Language: English


Light weight aerospace fastening collars were manufactured from 2099 alloy which is a new generation Al-Li alloy developed by Alcoa. The collars studied in this work are threaded self-locking collars with controlled torque-off feature and are to be used in a fastener assembly with a treated pin. The mechanical properties of 2099 collars were measured and compared to the ones made of incumbent alloys such as 7075 and 2024. It was found that the 2099 collars were 16% lighter but provided the equivalent mechanical properties.
In addition, the corrosion characteristics of the 2099 collars were studied using the salt spray and alternate immersion test methods. It was observed that 2099 collars exhibited an improved corrosion performance as compared to the base line 7075 collars. This paper presents the results obtained from the mechanical and corrosion testing of the Al-Li collars along with the weight saving potentials of the new product.