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4045 (BAlSi-5, AlSi10) Aluminum

4045 aluminum is a 4000-series aluminum alloy. The main alloying addition is silicon. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. 4045 is the Aluminum Association (AA) designation for this material. In European standards, it will be given as EN AW-4045. BAlSi-5 is the AWS designation. AlSi10 is the EN chemical designation. Additionally, the UNS number is A94045.

It originally received its standard designation in 1964.

The graph bars on the material properties cards below compare 4045 aluminum to: 4000-series alloys (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

71 GPa 10 x 106 psi

Elongation at Break

2.3 %

Fatigue Strength

45 MPa 6.5 x 103 psi

Poisson's Ratio

0.33

Shear Modulus

27 GPa 3.9 x 106 psi

Shear Strength

69 MPa 10 x 103 psi

Tensile Strength: Ultimate (UTS)

120 MPa 17 x 103 psi

Tensile Strength: Yield (Proof)

64 MPa 9.3 x 103 psi

Thermal Properties

Brazing Temperature

590 to 600 °C 1090 to 1120 °F

Latent Heat of Fusion

540 J/g

Maximum Temperature: Mechanical

160 °C 320 °F

Melting Completion (Liquidus)

600 °C 1110 °F

Melting Onset (Solidus)

580 °C 1070 °F

Specific Heat Capacity

900 J/kg-K 0.22 BTU/lb-°F

Thermal Conductivity

170 W/m-K 99 BTU/h-ft-°F

Thermal Expansion

21 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

45 % IACS

Electrical Conductivity: Equal Weight (Specific)

160 % IACS

Otherwise Unclassified Properties

Base Metal Price

9.5 % relative

Density

2.6 g/cm3 160 lb/ft3

Embodied Carbon

7.8 kg CO2/kg material

Embodied Energy

150 MJ/kg 63 x 103 BTU/lb

Embodied Water

1070 L/kg 130 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

2.4 MJ/m3

Resilience: Unit (Modulus of Resilience)

29 kJ/m3

Stiffness to Weight: Axial

15 points

Stiffness to Weight: Bending

54 points

Strength to Weight: Axial

13 points

Strength to Weight: Bending

21 points

Thermal Diffusivity

74 mm2/s

Thermal Shock Resistance

5.7 points

Alloy Composition

Among wrought aluminum alloys, the composition of 4045 aluminum is notable for containing a comparatively high amount of silicon (Si). Silicon is used to increase strength at the expense of ductility. It also lowers the melting temperature and raises the fluidity of the alloy.

Aluminum (Al) 87.4 to 91
Silicon (Si) 9.0 to 11
Iron (Fe) 0 to 0.8
Copper (Cu) 0 to 0.3
Titanium (Ti) 0 to 0.2
Zinc (Zn) 0 to 0.1
Manganese (Mn) 0 to 0.050
Magnesium (Mg) 0 to 0.050
Residuals 0 to 0.15

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

AWS A5.8: Specification for Filler Metals for Brazing and Braze Welding

Aluminum Standards and Data, Aluminum Association Inc., 2013

ASM Specialty Handbook: Aluminum and Aluminum Alloys, J. R. Davis (editor), 1993

EN 573-3: Aluminium and aluminium alloys. Chemical composition and form of wrought products. Chemical composition and form of products