772.0 Cast Aluminum
772.0 aluminum is an aluminum alloy formulated for casting. 772.0 is the Aluminum Association (AA) designation for this material. Additionally, the UNS number is A07720.
The properties of 772.0 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 772.0 aluminum to: ANSI/AA cast aluminums (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
6.3 to 8.4 %
Fatigue Strength
94 to 160 MPa 14 to 24 x 103 psi
Poisson's Ratio
0.32
Shear Modulus
26 GPa 3.8 x 106 psi
Tensile Strength: Ultimate (UTS)
260 to 320 MPa 38 to 47 x 103 psi
Tensile Strength: Yield (Proof)
220 to 250 MPa 32 to 36 x 103 psi
Thermal Properties
Latent Heat of Fusion
380 J/g
Maximum Temperature: Mechanical
180 °C 350 °F
Melting Completion (Liquidus)
630 °C 1160 °F
Melting Onset (Solidus)
580 °C 1080 °F
Specific Heat Capacity
870 J/kg-K 0.21 BTU/lb-°F
Thermal Conductivity
150 W/m-K 87 BTU/h-ft-°F
Thermal Expansion
24 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
35 % IACS
Electrical Conductivity: Equal Weight (Specific)
110 % IACS
Otherwise Unclassified Properties
Base Metal Price
9.5 % relative
Density
3.0 g/cm3 180 lb/ft3
Embodied Carbon
8.0 kg CO2/kg material
Embodied Energy
150 MJ/kg 64 x 103 BTU/lb
Embodied Water
1140 L/kg 140 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
16 to 25 MJ/m3
Resilience: Unit (Modulus of Resilience)
350 to 430 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
46 points
Strength to Weight: Axial
25 to 31 points
Strength to Weight: Bending
31 to 36 points
Thermal Diffusivity
58 mm2/s
Thermal Shock Resistance
11 to 14 points
Alloy Composition
Among cast aluminum alloys, the composition of 772.0 aluminum is notable for containing a comparatively high amount of zinc (Zn) and including chromium (Cr). 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. Chromium is used to limit grain growth during hot working or heat treatment, which improves ductility and toughness. Chromium also reduces the alloy's susceptibility to stress corrosion cracking. If the alloy is anodized, the presence of chromium will tend to add a yellow tint to the film.
| Al | 91.2 to 93.2 | |
| Zn | 6.0 to 7.0 | |
| Mg | 0.6 to 0.8 | |
| Ti | 0.1 to 0.2 | |
| Cr | 0.060 to 0.2 | |
| Si | 0 to 0.15 | |
| Fe | 0 to 0.15 | |
| Mn | 0 to 0.1 | |
| Cu | 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
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015