7108 (7108-T6) Aluminum
7108 aluminum is a 7000-series aluminum alloy: the main alloying addition is zinc and it is formulated for primary forming into wrought products. Cited properties are appropriate for the T6 temper. To achieve this temper, the metal is solution heat-treated and artificially aged until it meets standard mechanical property requirements. 7108 is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-7108. Additionally, the EN chemical designation is AlZn5Mg1Zr. The AFNOR (French) designation is A-Z56. And the UNS number is A97108.
It originally received its standard designation in 1983.
The graph bars on the material properties cards below compare 7108 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 %
Fatigue Strength
120 MPa 17 x 103 psi
Poisson's Ratio
0.33
Shear Modulus
26 GPa 3.8 x 106 psi
Shear Strength
210 MPa 31 x 103 psi
Tensile Strength: Ultimate (UTS)
350 MPa 51 x 103 psi
Tensile Strength: Yield (Proof)
290 MPa 42 x 103 psi
Thermal Properties
Latent Heat of Fusion
380 J/g
Maximum Temperature: Mechanical
210 °C 400 °F
Melting Completion (Liquidus)
630 °C 1170 °F
Melting Onset (Solidus)
530 °C 980 °F
Specific Heat Capacity
880 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
39 % IACS
Electrical Conductivity: Equal Weight (Specific)
120 % IACS
Otherwise Unclassified Properties
Base Metal Price
9.5 % 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 MJ/m3
Resilience: Unit (Modulus of Resilience)
620 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
47 points
Strength to Weight: Axial
34 points
Strength to Weight: Bending
38 points
Thermal Diffusivity
59 mm2/s
Thermal Shock Resistance
16 points
Alloy Composition
Among wrought aluminum alloys, the composition of 7108 aluminum is notable for containing a comparatively high amount of zinc (Zn) and including zirconium (Zr). 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. Zirconium is used to increase an alloy's recrystallization temperature, which increases the temperature at which the alloy can be used without permanent loss of mechanical properties.
| Al | 92.4 to 94.7 | |
| Zn | 4.5 to 5.5 | |
| Mg | 0.7 to 1.4 | |
| Zr | 0.12 to 0.25 | |
| Si | 0 to 0.1 | |
| Fe | 0 to 0.1 | |
| Mn | 0 to 0.050 | |
| Ti | 0 to 0.050 | |
| Cu | 0 to 0.050 | |
| res. | 0 to 0.15 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
EN 755-2: Aluminium and aluminium alloys. Extruded rod/bar, tube and profiles. Mechanical properties
Aluminum Standards and Data, Aluminum Association Inc., 2013
EN 573-3: Aluminium and aluminium alloys. Chemical composition and form of wrought products. Chemical composition and form of products
Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993