Duralumin (Age-Hardened Aluminium)
In the early 1900s Alfred Wilm found that an aluminium-copper alloy hardens by itself after quenching; sold as duralumin from 1909, it gave airships and aircraft light, strong frames.
Open in the interactive tree →Wilm noticed the effect around 1901-1903 in a Berlin-area laboratory, when hardness readings taken before a weekend were higher on Monday; the alloy of aluminium with about 4% copper plus magnesium and manganese was patented and sold from 1909 by Dürener Metallwerke as duralumin. Heat treatment makes fine copper-aluminium and magnesium-silicon particles form in the metal, which harden it. Rigid airships such as Graf Zeppelin and Hindenburg had duralumin frames, Junkers' first all-metal aircraft of 1915 used steel sheet but duralumin soon replaced it, the F 13 of 1919 had a duralumin skin and spars, and descendants such as alloy 2024 are still used for airframes.
Prerequisites
- Hall-Héroult Process (Aluminium)1886Cheap electrolytic aluminium is the base metal
Unlocks
- Zeppelins & Rigid Airships1900-1937Rigid airship frames were built of duralumin