Duralumin, also called duraluminum, duraluminium or dural is an alloy of aluminium (about 95%), copper (about 4%), and small amounts of magnesium (0.5%-1%) and manganese (less than 1%). It is far better in tensile strength than elemental aluminium, though less resistant to corrosion. Its heat and electrical conductivity are less than that of pure aluminium but much more than that of steel.
Duralumin was invented in 1908 by Alfred Wilm during research for the German army. Its first use was rigid airship frames. Its composition and heat-treatment were a wartime secret. With this new rip-resistant mixture, duralumin quickly spread throughout the aircraft industry in the early 1930s, where it was well suited to the new monocoque construction techniques that were being introduced at the same time. Duralumin also is popular for use in precision tools such as levels because of its light weight and strength.
Its use in ground vehicle components has been limited by cost of material and fabrication, relative to mild steel and cast iron, but it has become fairly common, especially in cases where requirements for acceleration, fuel efficiency, etc.
demand light weight. Duralumin components include wheels, cylinder heads, blocks, crank cases, oil sumps, manifolds, bodies or body parts (Land Rover, Honda Insight, Lotus Seven, Austin-Healey), frames (M2 Bradley fighting vehicle, a very high performance Chevrolet Corvette version, Messerschmitt KR200), bumpers and fuel tank (Panhard), differential case (Peugeot), bonnet (hood) and boot cover (trunk lid) (MG A).
Today almost all material that claims to be aluminium is actually an alloy thereof. Pure aluminium is encountered only when corrosion resistance is more important than strength or hardness. Copper-free aluminium is specified for such uses. Conversely, the term "alloy" usually means aluminium alloy.
In modern aircraft Duralumin has evolved into the alloys known as 2017, 2117,