Additive Aluminum Alloys
Additive aluminum alloys are the powders formulated for laser powder-bed fusion. Conventional wrought grades crack during printing (2000 and 7000 series especially), so the printable alloys start from the near-eutectic cast chemistry — AlSi10Mg, essentially a cast 360 alloy — and add scandium or zirconium to reach wrought-level strength. Parts are printed as one piece with internal channels and lattices that cannot be machined or cast.
Popular additive aluminum grades
Compare in the explorer| Grade | Yield, MPa | Tensile, MPa | Density, g/cm³ | Machinability | Weldability | Best for |
|---|---|---|---|---|---|---|
| AlSi10Mg | 265 | 460 | 2.67 | Fair | Good | The default powder-bed aluminum; heat exchangers, brackets |
| Scalmalloy | 285 | 400 | 2.67 | Good | Good | 7000-series-class strength and fatigue for aerospace |
| AlSi7Mg | 240 | 350 | 2.67 | Good | Very good | Higher ductility than AlSi10Mg (A356 chemistry) |
| AlSi12 | 250 | 400 | 2.67 | Fair | Very good | Thin walls and heat-transfer parts |
| 7A77 | 310 | 400 | 2.81 | Good | Poor | Aerospace 7000-series LPBF |
| A20X | 240 | 380 | 2.83 | Very good | Fair | Castable high-strength LPBF |
Choose additive aluminum for
Heat exchangers with internal channels, lightweight brackets and housings, ducting, lattice structures and consolidated assemblies — geometry that cannot be machined or cast, in quantities from one to a few hundred.
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Additive aluminum by application
- Heat exchangers and thermal parts
- AlSi10Mg and AlSi12: fine internal channels and thin fins, good conductivity, pressure-tight after stress relief; HIP if porosity must be zero.
- Structural brackets and housings
- AlSi10Mg (stress-relieved or T6) for strength close to 6061-T6; Scalmalloy where the bracket must match 7075 in strength or fatigue.
- Topology-optimised and lattice parts
- AlSi10Mg handles unsupported overhangs and lattices well; design for build orientation and 0.4–0.6 mm minimum walls.
Working with additive aluminum
- Process and post-processing
- Laser powder-bed fusion on a heated plate; parts are stress-relieved (about 300 °C, 2 h) before removal, then supports cut, surfaces blasted. As-built roughness is Ra 6–12 µm; machine datums and sealing faces.
- Heat treatment and properties
- AlSi10Mg as-built yields about 230 MPa with low ductility; stress relief trades some strength for ductility, a T6 cycle gives 6061-T6-class properties. Scalmalloy is aged (325 °C, 4 h) to about 480 MPa yield. Vertical build direction is 5–10 % weaker.
- Machining
- Machines like a cast Al-Si alloy — carbide tooling, moderate speeds, short chips; leave 0.5–1 mm stock on machined features. Threads are tapped or inserted after printing, not printed.
- Finishing
- Bead blast is standard; vibratory or chemical polishing smooths internal channels. Anodizing on AlSi10Mg comes out gray (high silicon); Scalmalloy anodizes more evenly. Chem-film and paint adhere well.
Other aluminum series
Additive Aluminum Alloys — frequently asked
What is additive aluminum?
Additive aluminum alloys are the powders formulated for laser powder-bed fusion. Conventional wrought grades crack during printing (2000 and 7000 series especially), so the printable alloys start from the near-eutectic cast chemistry — AlSi10Mg, essentially a cast 360 alloy — and add scandium or zirconium to reach wrought-level strength. Parts are printed as one piece with internal channels and lattices that cannot be machined or cast.
Which grade of additive aluminum should I use?
AlSi10Mg for almost everything: heat exchangers, brackets, housings and ducting, with strength close to 6061-T6 after stress relief and good surface finish. Scalmalloy when the part needs 7000-series-class strength and fatigue performance — aerospace brackets, motorsport uprights — at several times the powder cost. Al 7A77 and A20X are the alternatives in the same high-strength bracket. If the geometry does not need to be printed, a machined 6061 or 7075 part will be cheaper and better characterised.
Which grade of additive aluminum is the strongest?
7A77 has the highest yield strength in the series at 310 MPa; Scalmalloy follows at 285 MPa. Values are for each grade's default condition.
Which grade of additive aluminum is easiest to machine?
A20X (machinability very good, 70/100), then 7A77 (65/100).
AlSi10Mg or Scalmalloy?
AlSi10Mg for almost everything — it prints reliably, costs a fraction as much, and after T6 approaches 6061-T6 (≈ 250 MPa yield). Scalmalloy when the design needs 7075-class strength (≈ 480 MPa yield) or fatigue performance, typically aerospace brackets and motorsport parts, and the budget carries powder that costs several times more.
Why can’t 6061 or 7075 be 3D printed?
Their wide freezing range and high-strength composition hot-crack under the rapid solidification of laser powder-bed fusion. Printable aluminum starts from near-eutectic Al-Si chemistry (AlSi10Mg) or adds grain refiners such as scandium and zirconium (Scalmalloy, 7A77, A20X) to suppress cracking. Machining remains the way to get true 6061 and 7075 parts.