Aluminium alloy 2024 is an aluminium alloy, with copper as the primary alloying element. It is used in applications requiring high strength to weight ratio, as well as good fatigue resistance. It is not weldable, and has average machinability. Due to poor corrosion resistance, it is often clad with aluminium or Al-1Zn for protection, although this may reduce the fatigue strength.[1]
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Aluminum alloy 2024 has a density of 2.78 g/cm³ (0.1 lb/in³), electrical conductivity of 30% IACS, Young's Modulus of 73 GPa (10.6 Msi) across all tempers, and begins to melt at 500 °C (932 °F).[2]
2024 aluminum alloy's composition roughly includes 4.3-4.5% copper, 0.5-0.6% manganese, 1.3-1.5% magnesium and less than a half a percent of silicon, zinc, nickel, chromium, lead and bismuth.
The mechanical properties of 2024 depend greatly on the temper of the material.[1]
2024-O temper aluminium has no heat treating. It has a maximum tensile strength of 30-32 ksi (207-220 MPa), and maximum yield strength of no more than 14,000 psi (96 MPa). The material has elongation (stretch before ultimate failure) of 10-25%, this is the allowable range per applicable AMS specifications.
T3 temper 2024 sheet has an ultimate tensile strength of 58-62 ksi (400-427 MPa) and yield strength of at least 39-40 ksi (269-276 MPa). It has elongation of 10-15%.
T351 temper 2024 plate has an ultimate tensile strength of 68 ksi (470 MPa) and yield strength of 41 ksi (280 MPa). It has elongation of 19%.
Due to its high strength and fatigue resistance, 2024 is widely used in aircraft structures, especially wing and fuselage structures under tension.[3][4] Additionally, since the material is susceptible to thermal shock, 2024 is used in qualification of liquid penetrant tests outside of normal temperature ranges.[5]