Wrought Al alloys
1000 series are essentially pure aluminium with a minimum 99% aluminium content by weight and can be work hardened. 2000 series are alloyed with copper, can be precipitation hardened to strengths comparable to steel. Formerly referred to as duralumin, they were once the most common aerospace alloys, but were susceptible to stress corrosion cracking and are increasingly replaced by 7000 series in new designs. 3000 series are alloyed with manganese, and can be work hardened. 4000 series are alloyed with silicon. Variations of aluminium-silicon alloys intended for casting (and therefore not included in 4000 series) are also known as silumin. 5000 series are alloyed with magnesium, and offer superb corrosion resistance, making them suitable for marine applications. Also, 5083 alloy has the highest strength of not heattreated alloys. Most 5000 series alloys include manganese as well. 6000 series are alloyed with magnesium and silicon. They are easy to machine, are weldable, and can be precipitation hardened, but not to the high strengths that 2000 and 7000 can reach. 6061 alloy is one of the most commonly used general-purpose aluminium alloys. 7000 series are alloyed with zinc, and can be precipitation hardened to the highest strengths of any aluminium alloy (ultimate tensile strength up to 700 MPa for the 7068 alloy). Most 7000 series alloys include magnesium and copper as well. 8000 series are alloyed with other elements which are not covered by other series. Aluminium-lithium alloys are an example
Application of Aluminium in aircraft industry Al alloys are used in external structure, fuselage, wing skins, horizontal and vertical stabilisers and aircraft landing mats.