Overview
AZ31B Magnesium Alloy is the most widely used wrought magnesium alloy, offering an excellent combination of lightweight properties, moderate strength, good formability, vibration damping, machinability, and corrosion resistance.
The designation AZ31B indicates approximately 3% aluminum (A) and 1% zinc (Z) as the primary alloying elements. Due to its extremely low density and high specific strength, AZ31B is extensively used in aerospace, automotive, electronics, defense, and sporting goods industries.
AZ31B magnesium alloy is widely used in:
- Aerospace Components
- Automotive Parts
- Electronic Housings
- Sporting Equipment
- Medical Devices
- Defense Applications
- Lightweight Structural Components
- Precision Machined Parts
Because magnesium is the lightest structural metal available, AZ31B is often selected when weight reduction is a critical design requirement.
Material Specification
| Property | Value |
|---|---|
| Material Designation | AZ31B Magnesium Alloy |
| ASTM Standard | ASTM B90 / ASTM B107 |
| UNS Number | M11311 |
| Material Family | Magnesium-Aluminum-Zinc Alloy |
| Density | 1.77 g/cm³ |
| Magnetic Property | Non-Magnetic |
| Typical Supply Condition | Annealed (O), H24, H26 |
| Standard Forms | Sheet, Plate, Bar, Rod, Tube, Extrusions |
Chemical Composition
| Element | Content (%) |
|---|---|
| Magnesium (Mg) | Balance |
| Aluminum (Al) | 2.5–3.5 |
| Zinc (Zn) | 0.7–1.3 |
| Manganese (Mn) | 0.20–1.00 |
| Silicon (Si) | ≤0.10 |
| Copper (Cu) | ≤0.05 |
| Iron (Fe) | ≤0.005 |
| Nickel (Ni) | ≤0.005 |
The aluminum improves strength while zinc enhances mechanical properties and corrosion resistance.
Mechanical Properties
Annealed (O) Condition
| Property | Value |
|---|---|
| Tensile Strength | 230–260 MPa |
| Yield Strength | 145–170 MPa |
| Elongation | 10–18% |
| Hardness | 55–70 HB |
| Elastic Modulus | 45 GPa |
H24 Temper
| Property | Value |
|---|---|
| Tensile Strength | 260–290 MPa |
| Yield Strength | 180–220 MPa |
| Elongation | 8–12% |
Physical Properties
| Property | Value |
|---|---|
| Density | 1.77 g/cm³ |
| Melting Point | 566–632°C |
| Thermal Conductivity | 76 W/m·K |
| Electrical Conductivity | 22% IACS |
| Electrical Resistivity | 0.077 μΩ·m |
| Thermal Expansion Coefficient | 26 × 10⁻⁶/K |
| Specific Heat Capacity | 1040 J/kg·K |
Strength-to-Weight Ratio
| Material | Density (g/cm³) | Tensile Strength |
|---|---|---|
| AZ31B Magnesium | 1.77 | 260 MPa |
| Aluminum 6061-T6 | 2.70 | 310 MPa |
| Titanium Grade 2 | 4.51 | 345 MPa |
| 304 Stainless Steel | 8.00 | 515 MPa |
AZ31B provides one of the highest strength-to-weight ratios among commercially available structural metals.
Corrosion Resistance
| Environment | Performance |
|---|---|
| Indoor Environment | Good |
| Dry Atmosphere | Good |
| Fresh Water | Fair |
| Marine Atmosphere | Moderate |
| Salt Water | Poor |
| Industrial Environment | Fair |
Because magnesium is highly reactive, protective surface treatments are often recommended.
Recommended surface treatments:
- Chromate Conversion Coating
- Anodizing
- Powder Coating
- Electroplating
- Chemical Conversion Coating
- Painting
Vibration Damping Performance
| Property | Rating |
|---|---|
| Vibration Absorption | Outstanding |
| Noise Reduction | Excellent |
| Shock Absorption | Excellent |
AZ31B offers significantly better vibration damping than aluminum and steel, making it ideal for electronics and transportation applications.
Weldability
| Welding Process | Rating |
|---|---|
| TIG Welding | Good |
| MIG Welding | Good |
| Resistance Welding | Good |
| Laser Welding | Good |
Proper shielding gas and process control are required when welding magnesium alloys.
Machinability
| Process | Rating |
|---|---|
| CNC Turning | Excellent |
| CNC Milling | Excellent |
| Drilling | Excellent |
| Tapping | Excellent |
| Grinding | Good |
Machinability Comparison
| Material | Machinability |
|---|---|
| AZ31B Magnesium | Excellent |
| Aluminum 6061 | Excellent |
| Brass C360 | Excellent |
| Titanium Grade 5 | Moderate |
| Stainless Steel 304 | Moderate |
AZ31B machines very easily with low cutting forces and excellent chip formation.
Heat Treatment
Stress Relief
| Parameter | Value |
|---|---|
| Temperature | 150–260°C |
| Cooling Method | Air Cool |
Annealing
| Parameter | Value |
|---|---|
| Temperature | 345–415°C |
| Cooling Method | Air Cool |
Heat Treatability
| Property | Performance |
|---|---|
| Heat Treat Hardening | Limited |
| Annealing Response | Excellent |
| Cold Work Strengthening | Good |
AZ31B is primarily strengthened through work hardening rather than precipitation hardening.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM (USA) | AZ31B |
| UNS | M11311 |
| AMS | AMS 4375 |
| EN (Europe) | MgAl3Zn1 |
| DIN (Germany) | 3.3523 |
| ISO | AZ31B |
| JIS (Japan) | AZ31B |
| GB/T (China) | MB3 |
Available Forms
| Product Type | Availability |
|---|---|
| Sheet | Yes |
| Plate | Yes |
| Round Bar | Yes |
| Flat Bar | Yes |
| Tube | Yes |
| Extrusions | Yes |
| Forgings | Yes |
Typical Applications
Aerospace Industry
- Aircraft Interior Components
- Structural Panels
- Electronic Enclosures
- Lightweight Brackets
Automotive Industry
- Dashboard Frames
- Steering Components
- Seat Structures
- Transmission Housings
Electronics Industry
- Laptop Housings
- Camera Bodies
- Mobile Device Frames
- Electronic Enclosures
Defense Industry
- Lightweight Equipment
- Portable Systems
- Military Electronics
Medical Industry
- Medical Device Components
- Lightweight Equipment
- Imaging System Parts
Sporting Goods
- Bicycle Components
- Racing Equipment
- Performance Sports Products
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Machining | Outstanding |
| Forming | Good |
| Deep Drawing | Good |
| Welding | Good |
| Extrusion | Excellent |
| Surface Finishing | Excellent |
Advantages
Extremely Lightweight
Approximately 35% lighter than aluminum and 78% lighter than steel.
Excellent Machinability
High machining speeds and low tool wear.
Outstanding Vibration Damping
Superior noise and vibration reduction.
Good Strength-to-Weight Ratio
Suitable for lightweight structural applications.
Excellent Thermal Conductivity
Effective heat dissipation for electronic components.
Recyclable Material
Environmentally friendly and fully recyclable.
Limitations
Lower Corrosion Resistance
Requires protective coatings in harsh environments.
Lower Strength Than Titanium
Not suitable for extreme load-bearing applications.
Flammability Concerns During Machining
Proper chip handling and fire prevention measures are required.
Higher Material Cost Than Some Aluminum Alloys
Depending on application and supply conditions.
Comparison with Other Magnesium Alloys
| Property | AZ31B | AZ61A | AZ80A |
|---|---|---|---|
| Strength | Moderate | Higher | Highest |
| Formability | Excellent | Good | Moderate |
| Weldability | Good | Good | Fair |
| Machinability | Excellent | Excellent | Good |
Comparison with Common Lightweight Materials
| Material | Density | Tensile Strength | Machinability |
|---|---|---|---|
| AZ31B Magnesium | 1.77 g/cm³ | 260 MPa | Excellent |
| Aluminum 6061-T6 | 2.70 g/cm³ | 310 MPa | Excellent |
| Grade 2 Titanium | 4.51 g/cm³ | 345 MPa | Moderate |
| Carbon Steel A36 | 7.85 g/cm³ | 400 MPa | Good |
Available Surface Finishes
Raw Finishes
- Mill Finish
- Annealed Finish
Functional Finishes
- Precision Machined Finish
- Brushed Finish
- Polished Finish
Protective Finishes
- Anodized Finish
- Chromate Conversion Coating
- Powder Coating
- Painted Finish
Frequently Asked Questions (FAQ)
What is AZ31B magnesium alloy?
AZ31B is a magnesium alloy containing approximately 3% aluminum and 1% zinc, widely used for lightweight structural applications.
What is AZ31B used for?
Typical applications include:
- Aerospace Components
- Automotive Parts
- Electronic Housings
- Sporting Equipment
- Medical Devices
What is the equivalent material to AZ31B?
Common equivalents include:
- UNS M11311
- AMS 4375
- MgAl3Zn1
- MB3
What is the difference between AZ31B and 6061 aluminum?
| Property | AZ31B | 6061 Aluminum |
|---|---|---|
| Density | Lower | Higher |
| Weight Reduction | Better | Good |
| Corrosion Resistance | Lower | Better |
| Machinability | Similar | Similar |
Is AZ31B corrosion resistant?
AZ31B offers moderate corrosion resistance but generally requires protective coatings for outdoor or marine environments.
Can AZ31B be welded?
Yes. AZ31B can be welded using TIG, MIG, and laser welding processes.
Why choose AZ31B magnesium?
Because it combines:
- Extremely Low Weight
- Excellent Machinability
- Outstanding Vibration Damping
- Good Strength-to-Weight Ratio
- Excellent Formability
Is AZ31B suitable for aerospace applications?
Yes. AZ31B is widely used in aerospace interiors, structures, and lightweight assemblies.
Does GCNOV provide custom manufacturing services for AZ31B magnesium?
Yes. GCNOV provides:
- CNC Machining
- Precision Milling
- Magnesium Fabrication
- Surface Finishing
- Prototype Development
- Low-Volume Production
- Mass Production
- Custom Lightweight Components