When producing spare parts that demand both precision and reliability, choosing the right aluminum alloy is one of the most critical design decisions. Aluminum offers the unique combination of lightweight strength, excellent corrosion resistance, and thermal stability, but not all alloys behave the same in casting or end-use conditions.
Among the most widely used alloys in spare part manufacturing, three stand out for their distinct advantages: A380, ADC12, and AlSi10Mg.
Though similar in many ways, these alloys differ in castability, thermal performance, and mechanical properties, which makes each one better suited to specific applications—from high-pressure die-cast housings to lightweight structural components.
Why Aluminum Dominates the Spare Parts Market
Aluminum’s balance of weight reduction, mechanical strength, and corrosion protection makes it a perfect substitute for heavier ferrous materials. In industries ranging from automotive to electronics, it helps manufacturers achieve better fuel efficiency, easier assembly, and cleaner surface finishes.
Key advantages include:
- High strength-to-weight ratio, offering 60–70% mass savings over steel.
- Excellent corrosion resistance, with natural oxide protection.
- High thermal and electrical conductivity, making it ideal for motor housings and heat exchangers.
- Superior castability, compatible with high-pressure die casting (HPDC), low-pressure casting, and even 3D printing for prototypes.
A380 Aluminum
A380 is by far the most commonly specified aluminum alloy in high-pressure die casting. Found in everything from automotive housings and motor brackets to lighting enclosures, it offers an excellent balance between strength, dimensional stability, and cost-efficiency.
It flows well under high pressure, fills thin-walled molds without significant porosity, and maintains stable mechanical performance under thermal cycling.
Typical Composition (wt%)
| Si | Cu | Mg | Fe | Zn | Mn | Al |
|---|---|---|---|---|---|---|
| 7.5–9.5 | 3.0–4.0 | ≤0.3 | ≤1.3 | ≤3.0 | ≤0.5 | Balance |
Typical Mechanical Properties
| Property | Value |
|---|---|
| Ultimate Tensile Strength | 310 MPa |
| Yield Strength | 160 MPa |
| Elongation | 3–4% |
| Hardness (HB) | 80–90 |
| Density | 2.73 g/cm³ |
Because of its balanced composition, A380 remains the go-to choice for high-volume, medium-strength components. It’s stable, predictable, and compatible with standard surface treatments like powder coating, painting, and plating.
However, its slightly lower silicon content limits its fluidity compared to ADC12, meaning extremely thin-wall parts may require more precise process control.
ADC12 (Equivalent to A383)
While A380 dominates globally, ADC12 has become the regional workhorse alloy across Asia. It shares nearly identical mechanical strength with A380 but features higher silicon content, which gives it superior fluidity and better mold filling behavior—ideal for intricate die-cast parts.
Its properties make it especially favored for electronic housings, lighting fixtures, and thin-wall components that require smooth surfaces right out of the mold.
Typical Composition (wt%)
| Si | Cu | Mg | Fe | Zn | Ni | Al |
|---|---|---|---|---|---|---|
| 9.0–11.0 | 2.0–3.5 | ≤0.3 | ≤1.3 | ≤1.0 | ≤0.5 | Balance |
Typical Mechanical Properties
| Property | Value |
|---|---|
| Ultimate Tensile Strength | 320 MPa |
| Yield Strength | 165 MPa |
| Elongation | 2–3% |
| Hardness (HB) | 85–90 |
| Thermal Conductivity | 100–120 W/m·K |
Because ADC12 fills complex shapes easily, it’s particularly useful for thin sections below 2.5 mm or molds with intricate ribs and bosses.
Its smoother as-cast surface reduces secondary finishing work and improves coating adhesion.
In short: A380 is the all-rounder; ADC12 is the specialist for detail and surface quality.
AlSi10Mg – For Lightweight and Precision Applications
While A380 and ADC12 serve high-volume die casting, AlSi10Mg belongs to a different league.
Containing roughly 10% silicon and 0.3–0.5% magnesium, this alloy offers a unique blend of strength, ductility, and heat-treatability. It’s used in both gravity/low-pressure castings and additive manufacturing (AM), especially where weight reduction and thermal performance are crucial.
Typical Composition (wt%)
| Si | Mg | Cu | Fe | Al |
|---|---|---|---|---|
| 9.0–11.5 | 0.25–0.45 | ≤0.1 | ≤0.5 | Balance |
After T6 Heat Treatment
| Property | Value |
|---|---|
| Ultimate Tensile Strength | 340–400 MPa |
| Yield Strength | 230 MPa |
| Elongation | 6–10% |
| Thermal Conductivity | 130–150 W/m·K |
| Density | 2.65 g/cm³ |
These numbers show why AlSi10Mg is increasingly chosen for EV battery housings, aerospace brackets, and heat exchangers. It can withstand high operating temperatures while maintaining precise tolerances and low weight.
Unlike A380 or ADC12, it can undergo T6 or T7 heat treatment, enabling significant strength improvement.
It’s also compatible with 3D printing, allowing engineers to prototype complex internal channels or cooling fins before switching to mass casting.
Comparing A380, ADC12, and AlSi10Mg
| Criteria | A380 | ADC12 (≈A383) | AlSi10Mg |
|---|---|---|---|
| Casting Process | HPDC | HPDC | Gravity / LPDC / AM |
| Fluidity | Very good | Excellent | Moderate |
| Strength (UTS) | 310 MPa | 320 MPa | Up to 400 MPa |
| Elongation | 3–4% | 2–3% | 6–10% (T6) |
| Thermal Conductivity | ~90–110 W/m·K | ~100–120 W/m·K | 130–150 W/m·K |
| Corrosion Resistance | Good | Good | Excellent |
| Machinability | Excellent | Excellent | Moderate |
| Weight | Standard | Standard | Lightest |
| Best Use Case | Automotive & mechanical housings | Thin-wall & detailed castings | Precision, thermal & lightweight parts |
Choosing the Right Alloy for Spare Parts
| Application Type | Recommended Alloy | Why |
|---|---|---|
| High-volume die casting (automotive housings, brackets) | A380 | Cost-efficient, globally available |
| Thin-walled, complex designs (electronics, lighting) | ADC12 (≈A383) | Better fluidity and smoother finish |
| Lightweight & high-temperature environments (EV, aerospace) | AlSi10Mg | Stronger, heat-treatable, and thermally efficient |
| Prototype or 3D-printed validation models | AlSi10Mg | Ideal for additive manufacturing and low-volume runs |
The key is to match the alloy to your production scale, geometry, and end-use temperature.
A380 and ADC12 deliver unbeatable efficiency in mass production, while AlSi10Mg gives engineers the freedom to explore complex, performance-oriented designs.
Heat Treatment and Process Realities
One important distinction between these alloys lies in their response to heat treatment.
Both A380 and ADC12 are high-pressure die-cast alloys containing small gas porosity, which makes conventional T6 treatment risky—it can cause blistering or dimensional distortion.
Instead, these alloys rely on optimized die-casting parameters and surface finishing to reach their final properties.
AlSi10Mg, on the other hand, is fully heat-treatable, enabling higher strength and ductility without compromising stability. This makes it particularly attractive for structural and high-heat applications.
Real-World Applications
- A380: Engine brackets, gearbox housings, LED driver enclosures, and pump bodies.
- ADC12 (≈A383): Lighting fixtures, thin-wall electronic casings, motor end covers, compressor housings.
- AlSi10Mg: Battery trays, inverter housings, aerospace components, and precision mechanical parts.
At Yongzhu Casting, we produce all three alloys under controlled processes, combining high-pressure die casting (800–2000T machines) with CNC machining, spectrometer verification, and X-ray inspection to ensure every part meets international standards for mechanical and dimensional integrity.
Quick Equivalency Reference
| Region | A380 Equivalent | ADC12 Equivalent | AlSi10Mg Equivalent |
|---|---|---|---|
| USA (ASTM) | A380 | A383 | A360 family |
| Japan (JIS) | ADC10 | ADC12 | AC4MG |
| Europe (EN) | EN AC-46500 | EN AC-46000 | EN AC-43000 |
These equivalencies help global manufacturers maintain consistency in material sourcing and testing. However, due to subtle differences in impurities and silicon content, Yongzhu recommends verifying compositions by spectrometer before finalizing cross-regional replacements.
Conclusion
There’s no single “best” aluminum alloy—only the best match for your design and production goal.
- Choose A380 for cost-effective, large-scale casting with balanced performance.
- Choose ADC12 (≈A383) for thin-wall precision and high surface quality.
- Choose AlSi10Mg for heat-treatable, high-strength, or thermal-critical applications.
At Yongzhu Casting, we help OEMs and spare parts suppliers evaluate alloy selection based on application temperature, mechanical load, and surface requirements, ensuring that every project balances performance, quality, and manufacturing efficiency.
