Duralumin
Alloys · Common · Modern
Aluminium with a little copper in it, and the disconcerting habit of hardening while nobody is looking. Straight from the quench it is soft enough to shape; left on the bench it grows steadily stiffer over the following four days, and there is no undoing it. Aircraft factories packed their rivets in ice to keep them soft enough to drive.
Identity
- Source
- Modern alloy: aluminum, copper, magnesium, manganese
- Composition
- Aluminum ~94%, Copper ~4%, Magnesium ~1%, Manganese ~1%
- Over time
- Alfred Wilm's alloy of 1906. Its modern descendant, alloy 2024, holds 3.8 to 4.9% copper, 1.2 to 1.8% magnesium and 0.3 to 0.9% manganese.
- Also known as
- 2024 aluminum alloy, Aircraft aluminum
- Ores, before industry and since
- Azurite (Copper), Chalcocite (Copper), Chalcopyrite (Copper), Copper (Copper), Malachite (Copper), Tetrahedrite (Copper), Pyrolusite (Manganese)
- Ores of the industrial age
- Bauxite (Aluminum), Boehmite (Aluminum), Diaspore (Aluminum), Gibbsite (Aluminum), Bornite (Copper), Chrysocolla (Copper), Covellite (Copper), Cuprite (Copper), Enargite (Copper), Carnallite (Magnesium), Dolomite (Magnesium), Magnesite (Magnesium), Braunite (Manganese), Manganite (Manganese), Psilomelane (Manganese), Rhodochrosite (Manganese)
Physical Properties
- Appearance
- Silver-grey, lighter than steel, develops a white oxide coating
- Luster
- Metallic
- Density
- 2.78 g/cm³
- Melting point
- 650 °C
- Boiling point
- 2300 °C
- Lighter
- Aluminum
- Denser
- Mithral
- Magnetism
- Non-magnetic
- Electrical conductivity
- High
Mechanical Properties
- Mohs hardness
- 3.5
- Tensile strength
- 470 MPa
- Softer
- Shakudo
- Harder
- Hepatizon
- Workability
- Moderate
- Brittleness
- Moderate
- Malleability
- Moderate
- Ductility
- Moderate
Chemical Properties
- Corrosion resistance
- Moderate
- Reactivity
- Moderate
Lore & Narrative
Alfred Wilm found it in 1906 by accident, after a test that went wrong and a weekend that went by before he looked again. The Zeppelin airships were framed in duralumin, and so were the first all-metal aircraft.
- Notable uses
- Aircraft, spacecraft, transportation, sporting equipment
- Forge uses
- Aircraft, Spacecraft, Transportation
- Worldbuilding traits
- Lightweight, Aviation, Modern, Structural
Sources
- Duralumin, Wikipedia
- James Stevens Curl, Duralumin, A Dictionary of Architecture and Landscape Architecture, Encyclopedia.com
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