Duralumin

duralumin (drăl`yəmĭn, dy–), alloy of aluminum (over 90%) with copper (about 4%), magnesium (0.5%–1%), and manganese (less than l%). Before a final heat treatment the alloy is ductile and malleable; after heat treatment a reaction between the aluminum and magnesium produces increased hardness and tensile strength. Because of its lightness and other desirable physical properties, duralumin is widely used in the aircraft industry.

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Duralumin 

(also called duraluminum or dural), a collective name for a group of alloys based on aluminum and containing 3-5 percent copper, 0.4-2.4 percent magnesium, and 0.3-1.0 percent manganese. The Duralumin alloys were the first widely used deformable aluminum alloys. The phenomenon of hardening during natural aging was discovered with quenched duralumin.

The semicontinuous method is used to cast Duralumin into ingots, which undergo pressure treatment (rolling, pressing, and so on) to produce plates, sheets, sections, tubes, and wire for making rivets, forgings, and other intermediate products. Duralumin is quenched in water at a temperature of about 500°C and then undergoes natural aging for four days or, less frequently, artificial aging at about 190°C. After such heat treatment the ultimate strength of various grades of Duralumin is about 400-500 meganewtons per sq m (40-50 kilograms-force per sq mm). The initial period of development of metal airplane construction was associated with the manufacture of Duralumin. Along with aluminum alloys, Duralumin is widely used in aviation, surface transportation, and mechanical engineering.

REFERENCE

Bochvar, A. A. Metallovedenie, 5th ed. Moscow, 1956.

I. I. NOVIKOV