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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.

Aluminum (Al)Al 92.4 to 94.9
Copper (Cu)Cu 1.9 to 2.7
Magnesium (Mg)Mg 1.3 to 1.8
Iron (Fe)Fe 0.9 to 1.3
Nickel (Ni)Ni 0.9 to 1.2
Silicon (Si)Si 0.1 to 0.25
Titanium (Ti)Ti 0.040 to 0.1
Zinc (Zn)Zn 0 to 0.1
Residualsres. 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