Duralumin

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-resi…