Aluminum and aluminum based alloys are widely used in the aviation and defense industry due to their specific strength and high corrosion resistance. At the same time, their use in this industry has been significantly increased thanks to the weld ability of the aluminum alloys.
Aluminium alloys have been the main airframe materials since they startedreplacing wood in the late 1920s. Even though the role of aluminium in futureaircraft will probably be somewhat diminished by the increasing use of compositematerials, high-strength aluminium alloys are, and will remain, important airframematerials.
The attractiveness of aluminium is that it is a relatively low cost, lightweight metal that can be heat treated to fairly high-strength levels; and it is one of the most easily fabricated of the high-performance materials, which usually correlates directly with lower costs. Disadvantages of aluminium alloys include a low modulus of elasticity, rather low elevated-temperature capability (130 °C), and in high-strength alloys the susceptibility to corrosion.
Dramatic improvements in aluminium alloys have occurred since they were first introduced in the 1920s. These improvementsare a result ofincreasing understanding of chemical composition, impurity control and the effectsof processing and heat treatment. One of the earliest aerospace Al alloys was Duralumin (AA2017) which had ayield strength of 280 MPa. Property improvements have come through development of new alloy systems, modifications to compositions within particular systems,and from the use of a range of multistage ageing treatments (tempers).