2124 (2124-T851, AlCu4Mg1(A), 3.1354) Aluminum
2124 aluminum is a 2000-series aluminum alloy: the main alloying addition is copper, and it is formulated for primary forming into wrought products. Cited properties are appropriate for the T851 temper. To achieve this temper, the metal is solution heat-treated, stress relieved, then artificially aged. The stress relief is accomplished by stretching the metal by an amount that depends on the type of standard wrought product being made (sheet, plate, bar, or forging). 2124 is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-2124. AlCu4Mg1(A) is the EN chemical designation. Additionally, the UNS number is A92124.
It has been in use since 1960, but has only received its standard designation in 1970.
The graph bars on the material properties cards below compare 2124 aluminum to: 2000-series alloys (top), all aluminum alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
71 GPa 10 x 106 psi
Elongation at Break
5.7 %
Fatigue Strength
130 MPa 19 x 103 psi
Poisson's Ratio
0.33
Shear Modulus
27 GPa 3.9 x 106 psi
Shear Strength
280 MPa 41 x 103 psi
Tensile Strength: Ultimate (UTS)
490 MPa 71 x 103 psi
Tensile Strength: Yield (Proof)
430 MPa 62 x 103 psi
Thermal Properties
Latent Heat of Fusion
390 J/g
Maximum Temperature: Mechanical
190 °C 380 °F
Melting Completion (Liquidus)
640 °C 1180 °F
Melting Onset (Solidus)
500 °C 930 °F
Specific Heat Capacity
880 J/kg-K 0.21 BTU/lb-°F
Thermal Conductivity
150 W/m-K 88 BTU/h-ft-°F
Thermal Expansion
23 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
38 % IACS
Electrical Conductivity: Equal Weight (Specific)
110 % IACS
Otherwise Unclassified Properties
Base Metal Price
10 % relative
Density
3.0 g/cm3 190 lb/ft3
Embodied Carbon
8.2 kg CO2/kg material
Embodied Energy
150 MJ/kg 64 x 103 BTU/lb
Embodied Water
1150 L/kg 140 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
27 MJ/m3
Resilience: Unit (Modulus of Resilience)
1290 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
46 points
Strength to Weight: Axial
45 points
Strength to Weight: Bending
46 points
Thermal Diffusivity
58 mm2/s
Thermal Shock Resistance
21 points
Alloy Composition
Among wrought aluminum alloys, the composition of 2124 aluminum is notable for containing a comparatively high amount of copper (Cu). Copper is used to improve strength. This comes at the cost of a decrease in corrosion resistance and weldability.
| Al | 91.3 to 94.7 | |
| Cu | 3.8 to 4.9 | |
| Mg | 1.2 to 1.8 | |
| Mn | 0.3 to 0.9 | |
| Fe | 0 to 0.3 | |
| Zn | 0 to 0.25 | |
| Si | 0 to 0.2 | |
| Ti | 0 to 0.15 | |
| Cr | 0 to 0.1 | |
| res. | 0 to 0.15 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
Handbook of Aluminum Bonding Technology and Data, J. D. Minford, 1993
ASTM B209: Standard Specification for Aluminum and Aluminum-Alloy Sheet and Plate
Aluminum Standards and Data, Aluminum Association Inc., 2013
ASM Specialty Handbook: Aluminum and Aluminum Alloys, J. R. Davis (editor), 1993
ISO 6361-2: Wrought aluminium and aluminium alloys - Sheets, strips and plates - Part 2: Mechanical properties
EN 573-3: Aluminium and aluminium alloys. Chemical composition and form of wrought products. Chemical composition and form of products