707.0 (ZG42A, A07070) Cast Aluminum
707.0 aluminum is an aluminum alloy formulated for casting. 707.0 is the Aluminum Association (AA) designation for this material. A07070 is the UNS number. Additionally, the SAE designation is 312. Older literature may refer to this material as ASTM ZG42A, but this is now discouraged.
The properties of 707.0 aluminum include four common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare 707.0 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
70 GPa 10 x 106 psi
Elongation at Break
1.7 to 3.4 %
Fatigue Strength
75 to 140 MPa 11 to 20 x 103 psi
Poisson's Ratio
0.33
Shear Modulus
26 GPa 3.8 x 106 psi
Tensile Strength: Ultimate (UTS)
270 to 300 MPa 40 to 44 x 103 psi
Tensile Strength: Yield (Proof)
170 to 250 MPa 25 to 36 x 103 psi
Thermal Properties
Latent Heat of Fusion
380 J/g
Maximum Temperature: Mechanical
180 °C 360 °F
Melting Completion (Liquidus)
630 °C 1170 °F
Melting Onset (Solidus)
600 °C 1110 °F
Solidification (Pattern Maker's) Shrinkage
1.6 %
Specific Heat Capacity
880 J/kg-K 0.21 BTU/lb-°F
Thermal Conductivity
150 W/m-K 85 BTU/h-ft-°F
Thermal Expansion
24 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
37 % IACS
Electrical Conductivity: Equal Weight (Specific)
110 % 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 64 x 103 BTU/lb
Embodied Water
1140 L/kg 140 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
4.3 to 8.6 MJ/m3
Resilience: Unit (Modulus of Resilience)
210 to 430 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
47 points
Strength to Weight: Axial
26 to 29 points
Strength to Weight: Bending
32 to 34 points
Thermal Diffusivity
58 mm2/s
Thermal Shock Resistance
12 to 13 points
Alloy Composition
Among cast aluminum alloys, the composition of 707.0 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 | 90.5 to 93.6 | |
| Zn | 4.0 to 4.5 | |
| Mg | 1.8 to 2.4 | |
| Mn | 0.4 to 0.6 | |
| Fe | 0 to 0.8 | |
| Cr | 0.2 to 0.4 | |
| Ti | 0 to 0.25 | |
| Si | 0 to 0.2 | |
| Cu | 0 to 0.2 | |
| res. | 0 to 0.15 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B618: Standard Specification for Aluminum-Alloy Investment Castings
ASTM B108: Standard Specification for Aluminum-Alloy Permanent Mold Castings
ASTM B26: Standard Specification for Aluminum-Alloy Sand Castings
Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015