2018 (2018-T61) Aluminum
2018 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. 2018 is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-2018. Additionally, the UNS number is A92018.
It originally received its standard designation in 1954.
The graph bars on the material properties cards below compare 2018 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
73 GPa 11 x 106 psi
Elongation at Break
9.6 %
Fatigue Strength
120 MPa 17 x 103 psi
Poisson's Ratio
0.33
Shear Modulus
27 GPa 4.0 x 106 psi
Shear Strength
270 MPa 39 x 103 psi
Tensile Strength: Ultimate (UTS)
420 MPa 62 x 103 psi
Tensile Strength: Yield (Proof)
310 MPa 45 x 103 psi
Thermal Properties
Latent Heat of Fusion
390 J/g
Maximum Temperature: Mechanical
220 °C 430 °F
Melting Completion (Liquidus)
640 °C 1180 °F
Melting Onset (Solidus)
510 °C 940 °F
Specific Heat Capacity
870 J/kg-K 0.21 BTU/lb-°F
Thermal Conductivity
150 W/m-K 89 BTU/h-ft-°F
Thermal Expansion
22 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
40 % IACS
Electrical Conductivity: Equal Weight (Specific)
120 % IACS
Otherwise Unclassified Properties
Base Metal Price
11 % relative
Density
3.1 g/cm3 190 lb/ft3
Embodied Carbon
8.1 kg CO2/kg material
Embodied Energy
150 MJ/kg 64 x 103 BTU/lb
Embodied Water
1130 L/kg 130 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
37 MJ/m3
Resilience: Unit (Modulus of Resilience)
670 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
45 points
Strength to Weight: Axial
38 points
Strength to Weight: Bending
41 points
Thermal Diffusivity
57 mm2/s
Thermal Shock Resistance
19 points
Alloy Composition
Among wrought aluminum alloys, the composition of 2018 aluminum is notable for including nickel (Ni) and containing a comparatively high amount of copper (Cu). 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. Copper is used to improve strength. This comes at the cost of a decrease in corrosion resistance and weldability.
| Al | 89.7 to 94.4 | |
| Cu | 3.5 to 4.5 | |
| Ni | 1.7 to 2.3 | |
| Mg | 0.45 to 0.9 | |
| Fe | 0 to 1.0 | |
| Si | 0 to 0.9 | |
| Zn | 0 to 0.25 | |
| Mn | 0 to 0.2 | |
| 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
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
Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993