Alclad
Alclad is a corrosion-resistant aluminium sheet formed from high-purity aluminium surface layers metallurgically bonded (rolled onto) to high-strength aluminium alloy core material. It has a melting point of about 500 °C (932 °F). Alclad is a trademark of Alcoa but the term is also used generically.
Since the late 1920s, Alclad has been produced as an aviation-grade material, being first used by the sector in the construction of the
Details
The material was described in
As pure aluminium possesses a relatively greater resistance to corrosion over the majority of aluminium alloys, it was soon recognised that a thin coating of pure aluminium over the exterior surface of those alloys would take advantage of the superior qualities of both materials.[4] Thus, a key advantage of Alclad over most aluminium alloys is its high corrosion resistance.[5] However, considerable care must be taken while working on an Alclad-covered exterior surface, such as while cleaning the skin of an aircraft, to avoid scarring the surface to expose the vulnerable alloy underneath and prematurely age those elements.[4][6]
Due to its relatively shiny natural finish, it is often considered to be cosmetically pleasing when used for external elements, particularly during restoration efforts. It has been observed that some fabrication techniques, such as welding, are not suitable when used in conjunction with Alclad.[5] Mild cleaners with a neutral pH value and finer abrasives are recommended for cleaning and polishing Alclad surfaces. It is common for waterproof wax and other inhibitive coverings to be applied to further reduce corrosion.[4] In the twenty-first century, research and evaluation was underway into new coatings and application techniques.[7][8]
History
Alclad sheeting has become a widely used material within the
Alclad has been most commonly present in certain elements of an aircraft, including the fuselage, structural members, skin, and cowls.[5][12] The aluminium alloy that Alclad is derived from has become one of the most commonly used of all aluminium-based alloys.[13] While unclad aluminium has also continued to be extensively used on modern aircraft, which has a lower weight than Alclad, it is more prone to corrosion; the alternating use of the two materials is often defined by the specific components or elements that are composed of them. In aviation-grade Alclad, the thickness of the outer cladding layer typically varies between 1% and 15% of the total thickness.[11]
See also
- Kynal-Core, similar aluminium-clad alloys produced by ICI
- Duralumin, an aviation-related, copper-content aluminium alloy patented by its inventor Alfred Wilm by 1906
References
Citations
- ^ E. H. Dix, Jr. "A L C L A D" : New Corrosion Resistant Aluminum Product. NACA-TN-259. August 1927. Retrieved from NASA Technical Reports Server (NTRS) 26 Aug 2010.
- ^ a b Morrow and Fritsche 1967, p. iv.
- ISBN 978-0-9897906-0-4.
- ^ a b c "Corrosion Control – Part Seven (Corrosion of Aluminium/Aluminum Alloys)". flight-mechanic.com. Archived from the original on 23 July 2020. Retrieved 23 July 2020.
- ^ a b c d "Aluminium properties". experimentalaircraft.info. Retrieved 23 July 2020.
- ^ "Corrosion Control for Aircraft" (PDF). Federal Aviation Administration. 9 November 2018.
- S2CID 253466239.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link - ISBN 978-0-8031-2408-0.
- ^ J. Snodgrass and J. Moran. Corrosion Resistance of Aluminium Alloys. In Corrosion: Fundamentals, Testing and Protection, volume 13a of ASM Handbook. ASM, 2003.
- doi:10.1108/eb030845.
- ^ a b Kerster, Matt (28 May 2020). "Aluminum Aircraft Parts: Clad Aluminum Vs Bare Aluminum". aaaairsupport.com.
- .
- ^ "Aluminium Alloy 2024 (2024A)". aircraftmaterials.com. Retrieved 23 July 2020.
Bibliography
- Morrow, Walker C.; Carl B. Fritsche (1967). The Metalclad Airship ZMC-2. Grosse Ile: W.C. Morrow.