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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.

Aluminum (Al) 91.2 to 93.2
Zinc (Zn) 6.0 to 7.0
Magnesium (Mg) 0.6 to 0.8
Titanium (Ti) 0.1 to 0.2
Chromium (Cr) 0.060 to 0.2
Silicon (Si) 0 to 0.15
Iron (Fe) 0 to 0.15
Manganese (Mn) 0 to 0.1
Copper (Cu) 0 to 0.1
Residuals 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