7108A (AlZn5Mg1Zr) Aluminum
7108A aluminum is a 7000-series aluminum alloy: the main alloying addition is zinc and it is formulated for primary forming into wrought products. 7108A is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-7108A.
It originally received its standard designation in 1987.
The properties of 7108A aluminum include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare 7108A aluminum to: 7000-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
69 GPa 10 x 106 psi
Elongation at Break
11 to 13 %
Fatigue Strength
120 to 130 MPa 18 to 19 x 103 psi
Poisson's Ratio
0.33
Shear Modulus
26 GPa 3.8 x 106 psi
Shear Strength
210 MPa 30 to 31 x 103 psi
Tensile Strength: Ultimate (UTS)
350 MPa 50 to 51 x 103 psi
Tensile Strength: Yield (Proof)
290 to 300 MPa 42 to 43 x 103 psi
Thermal Properties
Latent Heat of Fusion
380 J/g
Maximum Temperature: Mechanical
210 °C 410 °F
Melting Completion (Liquidus)
630 °C 1170 °F
Melting Onset (Solidus)
520 °C 970 °F
Specific Heat Capacity
870 J/kg-K 0.21 BTU/lb-°F
Thermal Conductivity
150 W/m-K 86 BTU/h-ft-°F
Thermal Expansion
24 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
36 % IACS
Electrical Conductivity: Equal Weight (Specific)
110 % IACS
Otherwise Unclassified Properties
Base Metal Price
10 % relative
Density
2.9 g/cm3 180 lb/ft3
Embodied Carbon
8.3 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)
38 to 44 MJ/m3
Resilience: Unit (Modulus of Resilience)
610 to 640 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
47 points
Strength to Weight: Axial
33 to 34 points
Strength to Weight: Bending
38 points
Thermal Diffusivity
59 mm2/s
Thermal Shock Resistance
15 to 16 points
Alloy Composition
Among wrought aluminum alloys, the composition of 7108A aluminum is notable for including gallium (Ga) and containing a comparatively high amount of zinc (Zn). Gallium is used to improve corrosion resistance and to modify an alloy's response to etching, brightening, and similar treatments. Zinc is used to achieve significant increases in strength, at the cost of increased susceptibility to stress corrosion cracking. Among other things, this limits weldability.
| Al | 91.6 to 94.4 | |
| Zn | 4.8 to 5.8 | |
| Mg | 0.7 to 1.5 | |
| Zr | 0.15 to 0.25 | |
| Fe | 0 to 0.3 | |
| Si | 0 to 0.2 | |
| Mn | 0 to 0.050 | |
| Cu | 0 to 0.050 | |
| Cr | 0 to 0.040 | |
| Ti | 0 to 0.030 | |
| Ga | 0 to 0.030 | |
| 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 vol. 2: Alloy Production and Materials Manufacturing, George Totten and D. Scott MacKenzie (editors), 2003
Aluminum: Properties and Physical Metallurgy, John E. Hatch (editor), 1984
EN 755-2: Aluminium and aluminium alloys. Extruded rod/bar, tube and profiles. Mechanical properties
EN 573-3: Aluminium and aluminium alloys. Chemical composition and form of wrought products. Chemical composition and form of products