Material Name : GD-ALMg8Cu
Material Identification & Standards
GD-ALMg8Cu is a high-magnesium aluminum casting alloy (≈8% Mg) known for its excellent corrosion resistance and mechanical strength. Equivalent designations include:
- JIS (Japan): ADC5
- AA (USA): A518
- BS (UK): LM5 (BS 1490)
- DIN (Germany): GD‑ALMg8Cu (DIN 1725)
- ISO (International): Al‑Mg8 (ISO 3522)
- Common Use Type: Al‑Mg die casting alloy
- EN (Europe): EN AC‑51200 (EN 1706)
BS (UK)：No exact equivalent；LM5 (BS 1490) may be referenced as a base Al-Mg alloy, but does not match mechanical performance.
EN 1706 is a standard designation, officially titled:
EN 1706: Aluminium and aluminium alloys — Castings — Chemical composition and mechanical properties.
It is a European Standard (EN) that specifies the chemical composition and mechanical properties of cast aluminum alloys.
Therefore, all European cast aluminum alloys, such as EN AC‑44300, EN AC‑44100, EN AC‑43000, etc., are defined and governed under the framework of EN 1706.
Chemical Composition
- Aluminum (Al): Balance
- Magnesium (Mg): 7.5–8.5%
- Iron (Fe): ≤ 1.8%
- Silicon (Si): ≤ 0.35%
- Copper (Cu): ≤ 0.30%
- Manganese (Mn): ≤ 0.35%
- Nickel (Ni): ≤ 0.15%
- Tin (Sn): ≤ 0.15%
- Zinc (Zn): ≤ 0.15%
- Others: ≤ 0.25%
Mechanical & Physical Properties
| Property | Typical Value Range |
| Tensile Strength | ~310 MPa |
| Yield Strength | ~190 MPa |
| Elongation | ~5–8% |
| Brinell Hardness | ~80 HB |
| Density | ~2.6–2.8 g/cm³ |
| Melting Temperature | ~560–620 °C |
Thermal & Electrical Properties
| Property | Typical Value Range |
| Thermal Conductivity | ~80 – 100 W/m·K |
| Electrical Conductivity | 15 – 25 % IACS (~8.8–14.7 MS/m) |
| Thermal Expansion Coefficient | ~21 – 23 µm/m·K |
Pros & Cons Summary
| Feature | Pros | Cons |
| Strength & Hardness | High tensile (~310 MPa), good surface hardness (~80 HB) | Limited ductility (~5–8% elongation) |
| Corrosion Resistance | Excellent for marine, salt-spray, and chemical exposure | — |
| Machinability | Excellent, good polishing and finishing characteristics | — |
| Castability | Usable in die casting with special gating/cooling design | Prone to porosity and shrinkage defects |
Castability & Corrosion Resistance
GD-ALMg8Cu is suitable for pressure die casting but has low fluidity due to its high magnesium content. Proper gating design and controlled solidification are crucial to avoid defects such as porosity and hot cracking.
In terms of corrosion resistance, it performs exceptionally well in marine, chemical, and aggressive environments, making it ideal for critical components in outdoor or submerged applications.
Key Characteristics
- High magnesium content (7.5–8.5%) ensures strength and corrosion resistance
- Non-heat-treatable; strength derived from solidification structure
- Moderate elongation (~5–8%)
- High surface hardness (~80 HB)
- Good machinability and surface finish
- Requires precise casting control to minimize casting defects
Common Applications
- Marine / Offshore Equipment: Propeller housings, marine pumps, platform connectors
- Automotive & Motorcycle Components: Pump casings, engine mounts, brackets
- Aerospace & Sports Frames: High-load structural elements
- Industrial Hardware: Valve bodies, housing parts, corrosion-resistant machinery
Conclusion & Recommendation
GD‑ALMg8Cu is a high-strength, corrosion-resistant aluminum alloy suitable for applications demanding mechanical performance and environmental durability. It performs best in marine, automotive, and structural environments.
However, its casting requires specialized tooling and process control. It is not recommended for complex thin-wall parts that require excellent flowability—such cases may benefit more from Al‑Si based alloys like GD‑AlSi12.