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.
| Al | 87.4 to 91 | |
| Si | 9.0 to 11 | |
| Fe | 0 to 0.8 | |
| Cu | 0 to 0.3 | |
| Ti | 0 to 0.2 | |
| Zn | 0 to 0.1 | |
| Mn | 0 to 0.050 | |
| Mg | 0 to 0.050 | |
| res. | 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