308.0 (308.0-F, LM21, A03080) Cast Aluminum
308.0 aluminum is an aluminum alloy formulated for casting. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. 308.0 is the Aluminum Association (AA) designation for this material. LM21 is the British Standard (BS) designation. A03080 is the UNS number. Additionally, the AFNOR (French) designation is A-S5U2.
The graph bars on the material properties cards below compare 308.0 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
Brinell Hardness
70
Elastic (Young's, Tensile) Modulus
73 GPa 11 x 106 psi
Elongation at Break
2.0 %
Fatigue Strength
89 MPa 13 x 103 psi
Poisson's Ratio
0.33
Shear Modulus
27 GPa 3.8 x 106 psi
Shear Strength
150 MPa 22 x 103 psi
Tensile Strength: Ultimate (UTS)
190 MPa 28 x 103 psi
Tensile Strength: Yield (Proof)
110 MPa 16 x 103 psi
Thermal Properties
Latent Heat of Fusion
470 J/g
Maximum Temperature: Mechanical
170 °C 340 °F
Melting Completion (Liquidus)
620 °C 1140 °F
Melting Onset (Solidus)
540 °C 1000 °F
Specific Heat Capacity
870 J/kg-K 0.21 BTU/lb-°F
Thermal Conductivity
140 W/m-K 82 BTU/h-ft-°F
Thermal Expansion
20 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
37 % IACS
Electrical Conductivity: Equal Weight (Specific)
110 % IACS
Otherwise Unclassified Properties
Base Metal Price
10 % relative
Calomel Potential
-660 mV
Density
2.9 g/cm3 180 lb/ft3
Embodied Carbon
7.7 kg CO2/kg material
Embodied Energy
140 MJ/kg 62 x 103 BTU/lb
Embodied Water
1080 L/kg 130 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
3.3 MJ/m3
Resilience: Unit (Modulus of Resilience)
83 kJ/m3
Stiffness to Weight: Axial
14 points
Stiffness to Weight: Bending
47 points
Strength to Weight: Axial
18 points
Strength to Weight: Bending
25 points
Thermal Diffusivity
55 mm2/s
Thermal Shock Resistance
9.2 points
Alloy Composition
Among cast aluminum alloys, the composition of 308.0 aluminum is notable for containing a comparatively high amount of copper (Cu). Copper is used to improve strength. This comes at the cost of a decrease in corrosion resistance and weldability.
| Al | 85.7 to 91 | |
| Si | 5.0 to 6.0 | |
| Cu | 4.0 to 5.0 | |
| Fe | 0 to 1.0 | |
| Zn | 0 to 1.0 | |
| Mn | 0 to 0.5 | |
| Ti | 0 to 0.25 | |
| Mg | 0 to 0.1 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B108: Standard Specification for Aluminum-Alloy Permanent Mold Castings
Iron in Aluminium Alloys: Impurity and Alloying Element, N. A. Belov et al., 2002
ASM Specialty Handbook: Aluminum and Aluminum Alloys, J. R. Davis (editor), 1993