Each aluminum alloy has been carefully formulated and developed to enhance its use for specific types of applications. With the development of 2024 aluminum, copper was included as the primary alloying metal, which provided additional strength to the alloy without adding additional weight.
For this reason, 2024 is often used in the manufacturing of specific aircraft parts. These typically include the wing structure as well as the fuselage because of the extreme stress and tension on these components during flight.
Unfortunately, the use of copper in the alloy does reduce the 2024 aluminum corrosion resistance abilities. To address this problem, particularly on aircraft, the aluminum is typically coated or clad with another very thin layer of highly corrosion resistant aluminum. This alclad version offers top corrosion resistance and high strength to weight ratio, avoiding the problem of using 2024 that has not been clad.
With 2024 there is a significant amount of copper in the alloy, approximately 4.5 percent. There is also up to 1.5 percent of magnesium in the alloy, and then much lower percentages of manganese, bismuth, silicon, nickel, chromium, lead and zinc.
With this combination of alloys in the 2024 aluminum, it is rated to have average machinability, which means that it is not as difficult to work with as some aluminum alloys. The setting of the machining will be critical with higher machining speeds producing superior results when working with the alloy.
There is very poor weldability with the alloy. However, friction welding is highly effective. This is an advantage over some of the alloys which offer very low weldablility using any method.
The Temper Factor
The temper, or the way that the alloy is heat treated, will have an impact on the actual properties of the 2024 alloy. The tempers with this alloy, as with others, start with the designation of O, which indicates there is no heat treatment.
Without any heat treatment, this alloy and temper provide the lowest tensile and maximum yield strength, but it also provides the maximum elongation of up to 25%. The other end of the spectrum is 2024-T351, which has the highest tensile and yield strength but a lower elongation at 19%. Elongation is critical as it provides the percentage of stretch the alloy can achieve before failure.
While not as common of an alloy outside of the aircraft manufacturing industries, 2024 is a readily available aluminum alloy through top aluminum suppliers.