What is Aluminum Alloy AlSi10Mg?
AlSi10Mg is an aluminum–silicon–magnesium casting alloy with around 10 % Si and 0.3–0.6 % Mg. In EN standards it appears as grades such as EN AC-AlSi10Mg (e.g. EN AC-43000 / 43400 for sand, gravity and die casting). Thanks to its good castability for thin-wall, complex parts, high strength-to-weight ratio and solid corrosion resistance, it is widely used in automotive chassis components, aerospace brackets and housings, industrial machinery and robotics parts, heat-dissipating components such as brake calipers and heat sinks, and even 3D-printed metal parts.
In practical drawing language, “Material: AlSi10Mg” usually means a cast or pressure-die-cast aluminum part in this alloy family, supplied as-cast, stress-relieved or T6-type heat treated, then CNC-machined and surface-treated (anodizing, powder coating, etc.) to meet the final dimensional and durability requirements.
- Al–Si base with ~10 % silicon for excellent fluidity and low shrinkage in casting
- Magnesium addition (0.3–0.6 %) enables precipitation hardening and improves strength and fatigue resistance
- Low copper content compared with AlSi9Cu3 / EN AC-46000, giving better corrosion resistance and weldability
AlSi10Mg chemical composition and standards
Typical composition ranges (mass percent):
- Si: ~9.0–11.0 %
- Mg: ~0.25–0.6 %
- Fe: ≤0.55 % (controlled for good fatigue and weldability)
- Mn: ≤0.45 %
- Cu, Zn, Ni, Pb, Sn, Ti: usually each ≤0.1 %
- Al: balance
Different EN AC grades (e.g., 43000 vs 43400) mainly differ in impurity limits and whether the alloy is intended for gravity, sand, or pressure die casting.
For 3D-printed parts, powder suppliers use the same nominal chemistry but may specify even tighter limits on Fe and other trace elements to optimize mechanical performance.
Key AlSi10Mg material properties
When engineers search for “AlSi10Mg material properties”, they usually care about three pillars: mechanical strength, thermal behavior and corrosion resistance.
Note: Exact values depend strongly on casting process, wall thickness, heat treatment and quality level. The ranges below are typical, not guaranteed values.
Mechanical properties (typical ranges)
For well-made castings or AM parts with appropriate heat treatment, you can expect:
- Ultimate tensile strength (UTS): ~240–320 MPa for castings; up to ~400–460 MPa for optimized 3D-printed parts
- Yield strength (Rp0.2): ~150–220 MPa
- Elongation at break: ~3–10 % depending on section thickness and process route
- Brinell hardness: roughly 65–90 HB
- Young’s modulus: ~70–75 GPa
This combination makes AlSi10Mg stiffer and stronger than common die-casting alloys such as AlSi12, while still being easy to cast and machine.
Physical & thermal properties
Typical physical properties:
- Density: ~2.65–2.70 g/cm³
- Thermal conductivity: ~130–180 W/m·K (better than many steels and most 6000-series wrought alloys)
- Coefficient of thermal expansion: ~20–23 µm/m·K
- Electrical conductivity: about 25–30 % IACS
High thermal conductivity and low density make AlSi10Mg attractive for lightweight parts that must dissipate heat, like brake components, housings near engines, or heatsinks.
Corrosion resistance and surface treatments
Because copper is kept low and Mg/SI are balanced, AlSi10Mg offers:
- Good atmospheric and automotive corrosion resistance
- Better performance than AlSi9Cu3 in chloride environments (less risk of pitting)
- Very good compatibility with hard anodizing, conventional anodizing and conversion coatings, which further increase wear and corrosion resistance.
For critical parts, combining AlSi10Mg with hard-coat anodizing or plasma-electrolytic oxidation can give a tough, low-friction surface while keeping the lightweight core.
Where is AlSi10Mg used?
AlSi10Mg sits at the intersection of strength, castability and thermal performance, so it appears in many industries. Common applications include:
Automotive & commercial vehicles
- Chassis and suspension brackets
- Brake calipers and mounting carriers
- Steering and driveline housings
- Structural cross-members and crash-relevant brackets
Here the alloy helps reduce weight while keeping good fatigue resistance and stiffness.
Aerospace & defense
- Brackets and fittings for aircraft structures
- Housings for actuators, pumps and gearboxes
- Lightweight components made by 3D printing (topology-optimized brackets, ducts, heat exchangers)
Low density plus good fatigue performance make AlSi10Mg attractive where every kilogram saved matters.
Industrial machinery & robotics
- Gearbox housings and covers
- Robot arm joints and end-effectors
- Frames, clamps and jigs that must be rigid but easy to move
Thermal management and braking components
- Heat sinks and cooling plates
- High-temperature housings around engines or electric motors
- Brake calipers and carriers, where high thermal conductivity helps manage heat loads
Additive manufacturing (3D printing)
Selective laser melting (SLM) and similar processes commonly use AlSi10Mg powder to produce:
- Lattice structures
- Lightweight brackets with organic, topology-optimized shapes
- Conformal-cooled tooling inserts and heat exchangers
For buyers, this means you can often prototype parts in 3D-printed AlSi10Mg, then transition to cast AlSi10Mg once the geometry is frozen and volumes increase.
Casting vs 3D printing: how does AlSi10Mg behave?
Both casting and additive manufacturing rely on the same alloy family, but behavior differs:
- Casting (sand, gravity, HPDC)
- Best for medium to high volumes and thicker-walled parts
- Lower cost per piece once tooling exists
- Properties depend on cooling rate and porosity control; T6 heat treatment can improve strength and ductility
- Additive manufacturing (SLM, L-PBF)
- Ideal for complex internal channels and consolidating multiple parts into one
- Higher as-built strength but can show anisotropy and residual stress
- Powder cost and machine time keep unit cost high, so it’s suited to lower volumes or very high-value parts
When choosing a route, think in terms of annual volume, geometry complexity, tolerance requirements and budget. Our core business is high-pressure die casting and gravity casting of AlSi10Mg and other aluminum alloys; we often work alongside AM partners when projects start with 3D-printed prototypes.
Why choose AlSi10Mg instead of other aluminum alloys?
Engineers often compare AlSi10Mg with alternatives such as AlSi9Cu3, AlSi12, A380, or wrought alloys (6061, 6082, 7075).
In short:
- Versus AlSi9Cu3 / EN AC-46000 – AlSi10Mg usually gives better corrosion resistance, weldability and fatigue life, at the cost of slightly more demanding casting behavior and sometimes higher alloy price.
- Versus high-Si alloys (AlSi12) – AlSi10Mg offers higher strength and toughness, useful for structural parts, while AlSi12 may flow a bit better into extremely thin sections.
- Versus wrought alloys like 6061-T6 – Wrought alloys can achieve higher ductility and toughness but require extrusion/forging and extensive machining. AlSi10Mg casting delivers near-net shapes with far less material wastage and lower piece costs at volume.
If your part needs light weight, good strength, exposure to heat or corrosion, and efficient manufacturability, AlSi10Mg is often a strong candidate.
Design tips for AlSi10Mg castings
When you design an AlSi10Mg casting, you get the most benefit if you design for the process:
- Wall thickness & ribs
- Aim for uniform wall thickness where possible (2.5–6 mm is common, depending on process and part size).
- Use ribs and gussets to add stiffness instead of simply thickening walls; this reduces shrinkage defects and warpage.
- Fillets and transitions
- Avoid sharp internal corners; fillets of 0.5–2 mm help reduce stress concentration and improve metal flow.
- Smooth transitions between sections reduce hot spots and porosity.
- Tolerance strategy
- Use as-cast surfaces where tight tolerances are not required.
- Concentrate machined datums and functional features on accessible pads and bosses.
- Heat treatment planning
- Decide early whether the part will be delivered in as-cast, stress-relieved or T6-type condition; this influences achievable mechanical properties and dimensional stability.
- Surface engineering
- Consider anodizing or hard-coat anodizing for sliding surfaces, high-wear areas, or aggressive environments.
- For decorative parts, AlSi10Mg takes powder coating and painting very well with proper pre-treatment.
Discuss these points with your casting supplier while the design is still flexible—small changes in draft angles, rib layout or gating locations often pay back with lower scrap rates and better performance.
Working with an AlSi10Mg casting supplier
As an aluminum foundry, we typically support customers through:
- Alloy selection: confirming whether AlSi10Mg is the best fit or whether an alternative (AlSi9Cu3, AlSi12, etc.) would reduce cost or improve performance.
- DFM reviews: checking drawings for castability, tooling feasibility and machining strategy.
- Prototyping: sampling castings, validating material properties via mechanical and metallographic tests, and fine-tuning process parameters.
- Serial production: implementing robust HPDC or gravity-casting processes, in-line inspection and surface treatments to meet your quality standards.
If you’re evaluating aluminum AlSi10Mg for a new project or want to transfer existing parts to a new supplier, sharing your drawings, load cases and annual volume targets is the fastest way to get realistic recommendations on alloy choice, casting process and cost.
AlSi10Mg FAQ
1. What is AlSi10Mg typically used for?
AlSi10Mg is widely used for lightweight structural and dynamic parts that see repeated loading: automotive suspension and chassis components, aerospace brackets and seat structures, robot arms and joints, compressor and pump housings, brake calipers, heat sinks and other heat-dissipating components. In additive manufacturing it is also used for lattice structures, topology-optimized brackets and complex manifolds that are difficult to machine from solid.
2. How does AlSi10Mg compare with AlSi9Cu3 (EN AC-46000) or A380?
Compared with AlSi9Cu3 / A380-type alloys, AlSi10Mg contains much less copper and slightly more magnesium. This usually means:
- Better corrosion resistance and weldability than Cu-rich die casting alloys.
- Similar or slightly lower castability, but still very good for thin-wall parts.
- Higher potential strength and fatigue performance after T6-type heat treatment.
For high-volume automotive housings where cost and castability dominate, AlSi9Cu3 / A380 is still common; for structural, weldable or corrosion-sensitive parts, engineers often prefer AlSi10Mg.
3. Which manufacturing processes are suitable for AlSi10Mg?
AlSi10Mg can be processed by:
- High-pressure die casting (HPDC) for thin-wall, high-volume parts.
- Gravity and sand casting for larger, lower-volume components.
- Additive manufacturing (laser powder bed fusion / DMLS) using AlSi10Mg powder.
- Subsequent CNC machining to achieve tight tolerances and functional surfaces.
Choice of process depends on part size, complexity, tolerance requirements and annual volume.
4. Can AlSi10Mg be heat treated, and what properties can I expect?
Yes. AlSi10Mg responds well to solution treatment and artificial aging (T6-type tempers). Proper heat treatment can significantly increase yield and tensile strength and improve fatigue resistance, at the cost of a small reduction in ductility. For many structural parts, suppliers use a stress-relief or T5/T6-type cycle optimized to balance dimensional stability, strength and machinability.
5. Is AlSi10Mg weldable and can it be anodized?
AlSi10Mg is generally considered weldable, especially compared with Cu-rich Al-Si alloys. TIG and MIG welding are commonly used for repair, local reinforcement or attaching brackets. The alloy also anodizes well; clear or colored anodizing can improve corrosion resistance and give a technical appearance, provided the casting surface is properly prepared (removal of porosity, polishing or shot-blasting as required).
6. When should I choose AlSi10Mg instead of other aluminum casting alloys?
AlSi10Mg is a good choice when you need a combination of castability, mechanical strength, fatigue performance, corrosion resistance and weldability. Typical triggers to specify AlSi10Mg include:
- The part is load-bearing or safety-relevant and may require T6 heat treatment.
- The design needs welded joints or structural repairs later in the life cycle.
- The component works in corrosive or outdoor environments where Cu-rich alloys may suffer.
- You plan to use both casting and 3D printing for different versions of the same component and want a common alloy family.
