Key Takeaways
- AlSi10Mg is a lightweight aluminium alloy for DMLS.
- Good strength-to-weight and thermal conductivity.
- Ideal for lightweight brackets, housings, and heat sinks.
- Often post-heat-treated for improved properties.
AlSi10Mg is a cast aluminium alloy containing approximately 10% silicon and 0.3% magnesium. In DMLS (Direct Metal Laser Sintering), it has become the standard lightweight metal option — filling the gap between polymer SLS parts and the heavier stainless steel and titanium alloys. Layer X in Ahmedabad processes AlSi10Mg for aerospace, automotive, and electronics applications where the mass budget is tight but polymer mechanical properties fall short.
Mechanical Properties of DMLS AlSi10Mg
| Property | As-printed | T6 heat treated | Wrought Al 6061-T6 (reference) |
|---|---|---|---|
| Tensile strength (UTS) | 400–460 MPa | 330–380 MPa | 310 MPa |
| Yield strength (0.2%) | 230–270 MPa | 260–310 MPa | 276 MPa |
| Elongation at break | 3–5% | 6–10% | 12% |
| Hardness (HRB) | 70–80 | 60–70 | 60 |
| Density | 2.67 g/cm³ | 2.67 g/cm³ | 2.70 g/cm³ |
| Thermal conductivity | 100–130 W/m·K | 150–160 W/m·K | 167 W/m·K |
As-printed AlSi10Mg exceeds 6061-T6 in UTS due to rapid solidification producing a fine microstructure. T6 heat treatment (solution anneal + artificial ageing) reduces strength slightly but significantly improves ductility and isotropy.
Why DMLS Aluminium Outperforms Wrought in Complex Geometries
DMLS AlSi10Mg enables internal cooling channels, complex lattice infills, and organic topology-optimised shapes that are impossible or prohibitively expensive to machine from 6061 billet. For a heat sink or heat exchanger, conformal internal channels printed in AlSi10Mg can increase heat transfer efficiency by 30–50% compared to a conventionally machined block with straight drilled channels.
Topology-optimised aerospace brackets in AlSi10Mg routinely achieve 35–50% weight reduction versus machined equivalents while meeting the same structural requirements under documented design verification.
Heat Treatment Options
Three heat treatment variants are standard for DMLS AlSi10Mg:
- Stress relief only (300°C, 2h): Reduces residual stress from the build, minimises distortion during post-machining. Does not significantly change mechanical properties.
- T6 (solution treat 520°C, 1h + age 160°C, 12h): Maximises yield strength and improves ductility. Recommended for structural components.
- Direct ageing (170°C, 6h): Intermediate option — lower distortion risk than full T6, moderate property improvement. Used when dimensional change from solution treatment is unacceptable.
Surface Finishing and Anodising
DMLS AlSi10Mg can be anodised — both Type II (decorative) and Type III (hard anodise) are achievable. The silicon content affects anodise quality: the anodic layer is slightly darker than wrought aluminium and has lower breakdown voltage in hard anodise. For high-voltage or EMI shielding applications, consult Layer X before specifying hard anodise on DMLS parts.
As-printed surface roughness is Ra 6–12 µm on upward-facing surfaces, Ra 12–20 µm on downward-facing. CNC milling to datum faces brings this to Ra 0.8–1.6 µm; polishing to Ra 0.2–0.4 µm.
Design Guidelines for AlSi10Mg
- Minimum wall thickness: 0.4 mm (unsupported); 0.8 mm for structural walls
- Minimum channel diameter: 0.8 mm (self-supporting at 45° orientation)
- Add 0.5–1.0 mm stock to all machined faces
- Orient build to minimise support contact on cosmetic or sealing surfaces
- Avoid large flat overhanging surfaces — use stiffening ribs or slope the surface
AlSi10Mg is available at Layer X with standard delivery in 7–12 business days. Request a quote or see standard AlSi10Mg part pricing in the shop.