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 weldable only through friction welding, 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. In older systems of terminology, this alloy was named 24ST.
Contents
2024 is commonly extruded, and also available in alclad sheet and plate forms. It is not commonly forged (the related 2014 aluminum alloy is, though).
Basic properties
Aluminium 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).
2024 aluminium 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.
Mechanical properties
The mechanical properties of 2024 depend greatly on the temper of the material.
2024-O
2024-O temper aluminium has no heat treating. It has an ultimate tensile strength of 210–140 MPa (30–21 ksi), and maximum yield strength of no more than 97 MPa (14,000 psi). The material has elongation (stretch before ultimate failure) of 10-25%, this is the allowable range per applicable AMS specifications.
2024-T3
T3 temper 2024 sheet has an ultimate tensile strength of 400–430 MPa (58–62 ksi) and yield strength of at least 270–280 MPa (39–40 ksi). It has an elongation of 10-15%.
2024-T4
Solution treated and naturally aged.
2024-T5
Cooled from hot working and artificially aged (at elevated temperature)
2024-T351
T351 temper 2024 plate has an ultimate tensile strength of 470 MPa (68 ksi) and yield strength of 280 MPa (41 ksi). It has elongation of 20%.
Uses
Due to its high strength and fatigue resistance, 2024 is widely used in aircraft structures, especially wing and fuselage structures under tension. Additionally, since the material is susceptible to thermal shock, 2024 is used in qualification of liquid penetrant tests outside of normal temperature ranges.