2618 (2618-T61, 3.1924) Aluminum
2618 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 T61 temper. To achieve this temper, the metal is solution heat-treated and artificially underaged. The degree of underaging is different from T64 and T65. 2618 is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-2618. Additionally, the UNS number is A92618.
It has been in use since 1932, but has only received its standard designation in 1954.
The graph bars on the material properties cards below compare 2618 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
Brinell Hardness
120
Elastic (Young's, Tensile) Modulus
71 GPa 10 x 106 psi
Elongation at Break
5.8 %
Fatigue Strength
110 MPa 16 x 103 psi
Poisson's Ratio
0.33
Shear Modulus
27 GPa 3.9 x 106 psi
Shear Strength
260 MPa 38 x 103 psi
Tensile Strength: Ultimate (UTS)
420 MPa 61 x 103 psi
Tensile Strength: Yield (Proof)
350 MPa 51 x 103 psi
Thermal Properties
Latent Heat of Fusion
390 J/g
Maximum Temperature: Mechanical
210 °C 400 °F
Melting Completion (Liquidus)
640 °C 1180 °F
Melting Onset (Solidus)
550 °C 1020 °F
Specific Heat Capacity
880 J/kg-K 0.21 BTU/lb-°F
Thermal Conductivity
160 W/m-K 93 BTU/h-ft-°F
Thermal Expansion
22 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
37 % IACS
Electrical Conductivity: Equal Weight (Specific)
110 % IACS
Otherwise Unclassified Properties
Base Metal Price
11 % relative
Density
2.9 g/cm3 180 lb/ft3
Embodied Carbon
8.3 kg CO2/kg material
Embodied Energy
150 MJ/kg 65 x 103 BTU/lb
Embodied Water
1150 L/kg 140 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
23 MJ/m3
Resilience: Unit (Modulus of Resilience)
850 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
47 points
Strength to Weight: Axial
40 points
Strength to Weight: Bending
42 points
Thermal Diffusivity
62 mm2/s
Thermal Shock Resistance
19 points
Alloy Composition
Among wrought aluminum alloys, the composition of 2618 aluminum is notable for containing a comparatively high amount of iron (Fe) and including nickel (Ni). Most of the time, iron is an impurity in aluminum alloys. However, it may be added in quantity to improve strength (particularly at high temperatures) without much impact on electrical properties. Nickel is used to increase mechanical strength at elevated temperatures, and to reduce thermal expansion. However, it can increase susceptibility to pitting corrosion in certain alloys.
| Al | 92.4 to 94.9 | |
| Cu | 1.9 to 2.7 | |
| Mg | 1.3 to 1.8 | |
| Fe | 0.9 to 1.3 | |
| Ni | 0.9 to 1.2 | |
| Si | 0.1 to 0.25 | |
| Ti | 0.040 to 0.1 | |
| Zn | 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
ASTM B247: Standard Specification for Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
Iron in Aluminium Alloys: Impurity and Alloying Element, N. A. Belov et al., 2002
Aluminum Standards and Data, Aluminum Association Inc., 2013