Duralumin

Source: Wikipedia, the free encyclopedia.
Lakehurst Naval Air Station, NJ
on May 6, 1937
Corrosion of duralumin

Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of

age-hardenable aluminium–copper alloys. The term is a combination of Dürener and aluminium. Its use as a trade name is obsolete. Today the term mainly refers to aluminium-copper alloys, designated as the 2000 series by the international alloy designation system (IADS), as with 2014 and 2024
alloys used in airframe fabrication.

Duralumin was developed in 1909 in Germany. Duralumin is known for its strength and hardness, making it suitable for various applications, especially in the aviation and aerospace industry. However, it is susceptible to corrosion, which can be mitigated by using alclad-duralum materials.

History

Duralumin was developed by the German metallurgist

Aluminum Association
.

Composition

In addition to aluminium, the main materials in duralumin are copper, manganese and magnesium. For instance, Duraluminium 2024 consists of 91-95% aluminium, 3.8-4.9% copper, 1.2-1.8% magnesium, 0.3-0.9% manganese, <0.5% iron, <0.5% silicon, <0.25% zinc, <0.15% titanium, <0.10% chromium and no more than 0.15% of other elements together.[2] Although the addition of copper improves strength, it also makes these alloys susceptible to corrosion. Corrosion resistance can be greatly enhanced by the metallurgical bonding of a high-purity aluminium surface layer, referred to as alclad-duralum. Alclad materials are commonly used in the aircraft industry to this day.[3][4]

Microstructure

Applications

Aluminium alloyed with copper (Al-Cu alloys), which can be precipitation hardened, are designated by the International Alloy Designation System as the 2000 series. Typical uses for wrought Al-Cu alloys include:[5]

  • screw machine products. Applications where good machinability
    and good strength are required.
  • 2014: Heavy-duty forgings, plate, and extrusions for aircraft fittings, wheels, and major structural components, space booster tankage and structure, truck frame and suspension components. Applications requiring high strength and hardness including service at elevated temperatures.
  • 2017 or Avional (France): Around 1% Si.[6] Good machinability. Acceptable resistance to corrosion in air and mechanical properties. Also called AU4G in France. Used for aircraft applications between the wars in France and Italy.[7] Also saw some use in motor-racing applications from the 1960s,[8] as it is a tolerant alloy that could be press-formed with relatively unsophisticated equipment.
  • 2024
    :     Aircraft structures, rivets, hardware, truck wheels, screw machine products, and other structural applications.
  • 2036: Sheet for auto body panels
  • 2048: Sheet and plate in structural components for aerospace application and military equipment

Aviation

USS Akron (ZRS-4)

German scientific literature openly published information about duralumin, its composition and heat treatment, before the outbreak of

Flight, could still mis-identify its key alloying component as magnesium rather than copper.[9] Engineers in the UK showed little interest in duralumin until after the war.[10]

sesquiplane
of World War I

The earliest known attempt to use duralumin for a heavier-than-air aircraft structure occurred in 1916, when

Junkers J 7 single-seat fighter design, which led to the Junkers D.I low-wing monoplane fighter, introducing all-duralumin aircraft structural technology to German military aviation
in 1918.

Its first use in

USS Akron (ZRS-4) and USS Macon (ZRS-5).[11][12]

Bicycles

Duralumin was used to manufacture bicycle components and framesets from the 1930s to 1990s. Several companies in Saint-Étienne, France stood out for their early, innovative adoption of duralumin: in 1932, Verot et Perrin developed the first light alloy crank arms; in 1934, Haubtmann released a complete crankset; from 1935 on, Duralumin freewheels,

derailleurs
, pedals, brakes and handlebars were manufactured by several companies.

Complete framesets followed quickly, including those manufactured by: Mercier (and Aviac and other licensees) with their popular Meca Dural family of models, the Pelissier brothers and their race-worthy La Perle models, and Nicolas Barra and his exquisite mid-twentieth century “Barralumin” creations. Other names that come up here also included: Pierre Caminade, with his beautiful Caminargent creations and their exotic octagonal tubing, and also Gnome et Rhône, with its deep heritage as an aircraft engine manufacturer that also diversified into motorcycles, velomotors and bicycles after World War Two.

Mitsubishi Heavy Industries, which was prohibited from producing aircraft during the American occupation of Japan, manufactured the “cross” bicycle out of surplus wartime duralumin in 1946. The “cross” was designed by Kiro Honjo, a former aircraft designer responsible for the Mitsubishi G4M.[13]

Duralumin use in bicycle manufacturing faded in the 1970s and 1980s. Vitus (bicycle company) nonetheless released the venerable “979” frameset in 1979, a “Duralinox” model that became an instant classic among cyclists. The Vitus 979 was the first production aluminium frameset whose thin-wall 5083/5086 tubing was slip-fit and then glued together using a dry heat-activated epoxy. The result was an extremely lightweight but very durable frameset. Production of the Vitus 979 continued until 1992.[14]

Automotive

In 2011, BBS Automotive made the RI-D, the world's first production automobile wheel made of duralumin.[15] The company has since made other wheels of duralumin also, such as the RZ-D.[16]

References

  1. ^ J. Dwight. Aluminium Design and Construction. Routledge, 1999.
  2. ^ "United Aluminum - ALLOY 2024". Retrieved 8 October 2018.
  3. ^ J. Snodgrass and J. Moran. Corrosion Resistance of Aluminium Alloys. In Corrosion: Fundamentals, Testing and Protection, volume 13a of ASM Handbook. ASM, 2003.
  4. ISBN 978-0-9897906-0-4
    .
  5. ^ ASM Handbook. Volume 2, In Properties and Selection: Nonferrous alloys and special purpose materials. ASM, 2002.
  6. ISBN 9780871706911
    .
  7. Flight
    : 563. 27 June 1940.
  8. ISBN 9781845841966
    .
  9. Flight
    : 758. 7 September 1916.
  10. Flight: 680–684. Archived from the original
    on 2011-06-01.
  11. ^ Burton, Walter E. (October 1929). "The Zeppelin Grows Up". Popular Science Monthly: 26.
  12. ^ ""The Great Airships" Century of Flight". Archived from the original on 2018-04-26. Retrieved 2012-09-06.
  13. ^ Isurugi, Tatsuhito (September 3, 2013). ""Kaze tachinu" toujou jinbutsu to tori ningen kontesuto. Honjou Kirou no sengo" [A Character form “The Wind Also Rises” and the Japan Birdman Rally: Kiro Honjo’s Postwar]. news.yahoo.co.jp (in Japanese). Yahoo! Japan. Retrieved November 2, 2020.
  14. ^ Anschutz, Eric (October 31, 2020). "Duralumin History & Use in Bicycle Building". Ebykr. Anschutz Media. Retrieved November 1, 2020. Duralumin was used to manufacture bicycle components and framesets from the 1930s to 1990s.
  15. ^ "RI-D | BBS OFFICIAL WEBSITE ENGLISH" (in Japanese). Retrieved 2023-04-03.
  16. ^ "RZ-D | BBS OFFICIAL WEBSITE ENGLISH" (in Japanese). Retrieved 2023-04-03.
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