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2618A (2618A-T851, AlCu2Mg1.5Ni) Aluminum

2618A 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). 2618A is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-2618A. Additionally, the EN chemical designation is AlCu2Mg1,5Ni. The British Standard (BS) designation is H16. And the AFNOR (French) designation is A-U2GN.

It originally received its standard designation in 1972.

The graph bars on the material properties cards below compare 2618A 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

72 GPa 10 x 106 psi

Elongation at Break

4.5 %

Fatigue Strength

120 MPa 18 x 103 psi

Poisson's Ratio

0.33

Shear Modulus

27 GPa 3.9 x 106 psi

Shear Strength

260 MPa 37 x 103 psi

Tensile Strength: Ultimate (UTS)

440 MPa 64 x 103 psi

Tensile Strength: Yield (Proof)

410 MPa 60 x 103 psi

Thermal Properties

Latent Heat of Fusion

390 J/g

Maximum Temperature: Mechanical

230 °C 450 °F

Melting Completion (Liquidus)

670 °C 1240 °F

Melting Onset (Solidus)

560 °C 1040 °F

Specific Heat Capacity

880 J/kg-K 0.21 BTU/lb-°F

Thermal Conductivity

150 W/m-K 89 BTU/h-ft-°F

Thermal Expansion

23 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

3.0 g/cm3 180 lb/ft3

Embodied Carbon

8.4 kg CO2/kg material

Embodied Energy

150 MJ/kg 66 x 103 BTU/lb

Embodied Water

1150 L/kg 140 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

19 MJ/m3

Resilience: Unit (Modulus of Resilience)

1180 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

47 points

Strength to Weight: Axial

41 points

Strength to Weight: Bending

44 points

Thermal Diffusivity

59 mm2/s

Thermal Shock Resistance

19 points

Alloy Composition

Among wrought aluminum alloys, the composition of 2618A 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.

Aluminum (Al)Al 91.5 to 95.2
Copper (Cu)Cu 1.8 to 2.7
Magnesium (Mg)Mg 1.2 to 1.8
Iron (Fe)Fe 0.9 to 1.4
Nickel (Ni)Ni 0.8 to 1.4
Silicon (Si)Si 0.15 to 0.25
Manganese (Mn)Mn 0 to 0.25
Zirconium (Zr)Zr 0 to 0.25
Titanium (Ti)Ti 0 to 0.2
Zinc (Zn)Zn 0 to 0.15
Residualsres. 0 to 0.15

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

Iron in Aluminium Alloys: Impurity and Alloying Element, N. A. Belov et al., 2002

EN 485-2: Aluminium and aluminium alloys. Sheet, strip and plate. Mechanical properties

EN 573-3: Aluminium and aluminium alloys. Chemical composition and form of wrought products. Chemical composition and form of products

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015