# 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 10 ^{6} psi*

Elongation at Break

2.0 *%*

Fatigue Strength

89 *MPa* 13 *x 10 ^{3} psi*

Poisson's Ratio

0.33

Shear Modulus

27 *GPa* 3.8 *x 10 ^{6} psi*

Shear Strength

150 *MPa* 22 *x 10 ^{3} psi*

Tensile Strength: Ultimate (UTS)

190 *MPa* 28 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

110 *MPa* 16 *x 10 ^{3} 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/cm ^{3}* 180

*lb/ft*

^{3}Embodied Carbon

7.7 *kg CO _{2}/kg material*

Embodied Energy

140 *MJ/kg* 62 *x 10 ^{3} BTU/lb*

Embodied Water

1080 *L/kg* 130 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

3.3 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

83 *kJ/m ^{3}*

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 *mm ^{2}/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