AZ91D Magnesium Alloy Specification
High-Strength Cast Magnesium Alloy for Lightweight Applications
Product Specification
| Standard | ASTM B94, AMS 4481, GB/T 13820 |
| Material Designation | AZ91D (Mg-9Al-1Zn), UNS M11916 |
| Temper Conditions | F (As Cast), T4 (Solution Treated), T6 (Solution & Aged) |
| Alloy Type | Cast Magnesium-Aluminum-Zinc Alloy |
| Available Forms | Sand Castings Die Castings (High Pressure) Permanent Mold Castings Investment Castings |
Chemical Composition (wt%)
| Element | Min | Max | Role |
| Aluminum (Al) | 8.5 | 9.5 | Primary strengthening element, improves castability |
| Zinc (Zn) | 0.45 | 0.9 | Secondary strengthening, enhances corrosion resistance |
| Manganese (Mn) | 0.17 | 0.5 | Improves corrosion resistance, forms Al-Mn compounds |
| Magnesium (Mg) | Balance | Base element, provides lightweight structure | |
| Silicon (Si) | – | 0.10 | Impurity control |
| Copper (Cu) | – | 0.030 | Impurity control (reduces corrosion resistance) |
| Iron (Fe) | – | 0.005 | Impurity control (reduces corrosion resistance) |
| Nickel (Ni) | – | 0.002 | Impurity control (reduces corrosion resistance) |
| Other Impurities | – | 0.02 each | Impurity control |
Mechanical Properties
| Property | As Cast (F) | T6 Temper | Condition |
| Tensile Strength | 160-200 MPa | 230-275 MPa | Room temperature |
| Yield Strength (0.2%) | 80-110 MPa | 130-160 MPa | Room temperature |
| Elongation | 1-3% | 2-4% | In 50mm |
| Compressive Yield Strength | 80-110 MPa | 130-160 MPa | Room temperature |
| Shear Strength | 115-140 MPa | 140-170 MPa | Room temperature |
| Fatigue Strength | 70-90 MPa | 90-120 MPa | 10⁷ cycles, R=-1 |
| Hardness (Brinell) | 60-70 HB | 75-85 HB | 500 kgf, 10mm ball |
Physical Properties
- Density: 1.81 g/cm³
- Melting Range: 470-595°C
- Thermal Conductivity: 51 W/(m·K)
- Thermal Expansion: 26.1×10⁻⁶/°C (20-100°C)
- Electrical Conductivity: 30% IACS
- Modulus of Elasticity: 45 GPa
- Specific Heat: 1050 J/(kg·K)
- Damping Capacity: Excellent
- EMI Shielding Effectiveness: 70-100 dB
Casting Characteristics
AZ91D exhibits excellent die-casting characteristics with high fluidity, low hot cracking tendency, and good pressure tightness. It can be cast with wall thicknesses as low as 1.0-1.5mm in die-casting applications. The alloy has a relatively narrow freezing range, which reduces shrinkage porosity and improves dimensional stability.
Corrosion Consideration
AZ91D offers significantly better corrosion resistance than earlier AZ91 alloys due to strict control of iron, nickel, and copper impurities. However, proper surface protection (conversion coating, anodizing, painting, or plating) is recommended for long-term service in corrosive environments, particularly when exposed to saltwater or acidic conditions.
Applications
- Automotive: Transmission cases, steering column components, intake manifolds
- Electronics: Laptop cases, camera bodies, mobile device housings
- Industrial: Power tool housings, machinery components, equipment enclosures
- Consumer Goods: Lawn and garden equipment, sporting goods, luggage frames
- Aerospace: Non-structural aircraft components, electronic enclosures
Processing Guidelines
- Die casting: Use hot chamber process for small parts, cold chamber for larger parts
- Heat treatment: T4 (solution treat at 410°C for 4-16h), T6 (solution treat + age at 175°C for 8-16h)
- Machining: Use sharp tools, adequate cooling, and proper chip evacuation
- Joining: Can be welded using TIG, but casting defects may limit weldability
- Surface treatment: Apply conversion coating or anodizing for corrosion protection
Key Advantages
- Excellent castability for complex, thin-walled components
- High strength-to-weight ratio among magnesium alloys
- Good corrosion resistance (for a magnesium alloy)
- Excellent electromagnetic interference (EMI) shielding
- Good machinability with high cutting speeds possible
- 100% recyclable with minimal energy requirements
Document generated on February 4, 2026 at 04:17 PM
AZ91D Magnesium Alloy Specification | © 2023 Advanced Materials Institute
Data for reference only. Actual properties may vary based on processing conditions and specific lot characteristics.
