Magnesium alloys are mixtures of magnesium with other metals like aluminum, zinc, and manganese. These combinations offer different properties that suit specific needs. Magnesium, one of the lightest structural metals, makes these alloys ideal for reducing product weight.
Magnesium alloys exhibit good fatigue and creep resistance. The specific composition of these alloys is chosen to enhance certain characteristics, making them versatile in design and manufacturing.
Advantages of Magnesium Alloys
The most significant benefit is the high strength-to-weight ratio. This means they are strong yet light, which is ideal for industries needing to reduce weight without compromising strength.
Magnesium alloys are also easily processed through the die-casting process. This allows the creation of complex parts with high precision. Their ability to dampen vibrations makes them beneficial in reducing noise and wear in mechanical parts. Additionally, they have excellent heat dissipation properties, which are suitable for electronic devices and other applications.
Different Magnesium Alloy Properties and Their Properties
| Alloy | Density (g/cm³) | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Al Content (%) | Zn Content (%) | Other Elements |
|---|---|---|---|---|---|---|---|
| AZ91 | 1.81 | 200-260 | 140-170 | 1-6 | 8.3-9.7 | 0.35-1.0 | 0.15-0.50% Mn |
| AM60 | 1.80 | 190-250 | 120-150 | 4-14 | 5.5-6.5 | 0.1 | 0.35% Mn |
| AM50 | 1.77 | 180-230 | 110-130 | 5-15 | 4.5-5.5 | 0.1 | 0.35% Mn |
| AM20 | 1.75 | 150-220 | 80-100 | 8-18 | 1.6-2.6 | 0.2 (max) | 0.1% Mn (min) |
| AZ80 | 1.81 | Not specified | Not specified | Not specified | 7.8-9.2 | 0.2-0.8 | 0.15-0.5% Mn |
| WE54 | 1.74 | Not specified | Not specified | Not specified | – | – | Y, RE, Zr |
| WE43 | 1.74 | Not specified | Not specified | Not specified | – | – | Y, RE, Zr |
Melting point of different magnesium alloy
| Magnesium Alloy | Melting Point Range (°C) | Melting Point Range (°F) |
|---|---|---|
| Pure Magnesium | 650 | 1202 |
| AZ91D | 470 – 595 | 875 – 1105 |
| AM60B | 540 – 615 | 1005 – 1140 |
| AM50A | 540 – 620 | 1005 – 1150 |
| AM20 | 545 – 630 | 1015 – 1165 |
| AE42 | 590 – 620 | 1095 – 1150 |
| WE54 | 540 – 640 | 1005 – 1185 |
| WE43 | 540 – 640 | 1005 – 1185 |
| Elektron 21 | 550 – 640 | 1022 – 1184 |
| ZK60A | 530 – 635 | 985 – 1175 |
What are the Differences Between the Commonly Used AZ91 and AM60B?
AZ91 has higher aluminum compared to AM60B, giving AZ91 higher strength but lower ductility. Meanwhile, AZ91 contains more zinc, which improves strength and corrosion resistance.
In real application, AM60B offers better ductility and energy absorption, making it suitable for safety-critical components, while AZ91 provides higher strength and better corrosion resistance, making it ideal for structural components and housings.
What are the Properties of Die Cast Magnesium？
Mechanical Characteristics
Die-cast magnesium alloys, like AZ91D, are known for their remarkable mechanical properties. These alloys not only provide high strength but also maintain a lightweight profile. Toughness and tolerance are other aspects you’ll appreciate, making these alloys suited for demanding applications.
The metal’s microstructure is fine and contributes to enhanced durability. Magnesium alloys often deliver a good combination of tensile and yield strength, which means they can handle stress well without failing. This quality makes them great for structural applications.
Corrosion Resistance and Surface Finish
Magnesium die-cast parts are known for good corrosion resistance. This is crucial in environments where moisture could be a problem. Moreover, surface finish is another area where these alloys shine. The smooth surface makes painting or coating easier, giving you flexibility in finishing options.
Advanced treatments can further improve the corrosion resistance and longevity. These properties make magnesium alloys ideal for outdoor or industrial environments where surfaces are exposed to harsh conditions. Offering both function and aesthetics, these alloys are highly versatile.
What is the Process of Magnesium Die Casting？
Magnesium die casting involves precise methods that shape metal into strong, durable parts. Two important processes are Hot-Chamber Die Casting and High-Pressure Die Casting. Each method has its own strengths and uses depending on the application.
Hot-Chamber Die Casting
The machinery and mold setup of Hot-Chamber Die Casting makes it a great choice for magnesium alloys. The process involves a chamber, or “gooseneck,” that’s submerged in the molten metal. An injection mechanism presses this melted alloy into the die cavity. This setup helps with quick cycle times, making it efficient and suitable for small die cast parts production.
You’ll find it used in industries demanding durable, lightweight components, such as consumer electronics or small engine housings. This method benefits from its operational simplicity, though the melting chamber’s exposure can lead to metal contamination.
High-Pressure Die Casting
High-Pressure Die Casting is widely used for structural applications, especially when components need exacting details. It involves injecting molten magnesium under substantial pressure into robust steel molds known as dies.
This technique allows for the creation of parts with thin walls and smooth surfaces, ideal for sectors like automotive and aerospace. The high pressure used ensures the metal quickly fills the entire mold, capturing intricate designs. While effective, the equipment or machine costs and technical expertise needed are higher compared to other methods.
Advantages and Disadvantages of Magnesium Die Casting
Advantages:
- 1. Extremely lightweight – Magnesium is 75% lighter than steel and 33% lighter than aluminum.
- 2. Excellent strength-to-weight ratio.
- 3. Fast production cycle times due to quick solidification.
- 4. Ability to cast thin walls and fine details.
- 5. Good dimensional stability and accuracy.
- 6. Excellent machinability.
- 7. Good thermal and electrical conductivity.
- 8. Excellent vibration and noise-dampening properties.
- 9. Good EMI/RFI shielding capabilities.
- 10. Fully recyclable material.
- 11. Longer die life compared to aluminum die casting.
Disadvantages:
- 1. Higher raw material cost compared to aluminum or zinc.
- 2. Lower stability/rigidity compared to aluminum parts.
- 3. Requires more post-production processing.
- 4. Higher overall production costs compared to aluminum or zinc die casting.
- 5. More susceptible to corrosion than some other metals, requiring protective measures.
- 6. Specialized knowledge and equipment are required for optimal results.
- 7. Higher initial tooling costs for complex die.
What are the Applications of Magnesium Die Casting
Automotive and Aerospace Industries
In these industries, lightweight materials are critical for efficiency and performance. Die casting magnesium parts are favored because they weigh less than aluminum and steel. This means vehicles can go farther and use less fuel. It’s used in parts like engine blocks and gearboxes to reduce overall vehicle weight.
Die-cast magnesium also plays a role in the aerospace sector. Airplanes use it in components like seat frames and structural parts, benefiting from the lightweight nature of the metal without sacrificing durability. This is vital in reducing fuel consumption.
Consumer Electronics
When it comes to consumer electronics, magnesium alloys serve as a robust and lightweight option. Laptops and smartphones often incorporate magnesium die castings in their cases. This keeps devices both durable and portable.
These alloys also provide superior RFI shielding, protecting sensitive electronics from interference while improving performance. The combination of the strength and weight of magnesium makes it a go-to choice for electronics manufacturers focused on high-quality, lightweight products. This allows for sleek designs that are both strong and stylish.
Frequently Asked Questions
What are the advantages of using magnesium in die casting compared to other metals?
Magnesium is one of the lightest structural metals available. It provides an excellent strength-to-weight ratio, which is why it’s favored in industries like automotive and aerospace. Additionally, magnesium offers good corrosion resistance and efficient heat dissipation.
How does the magnesium casting process differ from other metal casting methods?
Unlike aluminum or zinc, magnesium can be cast using both hot chamber and cold chamber methods. The choice depends on production needs like speed and complexity. High-pressure injection and rapid cooling are key steps, ensuring accuracy and precision.
What are the safety precautions needed when casting magnesium?
Magnesium is flammable, so proper safety measures are crucial. Ensure you have a well-ventilated workspace and fire safety equipment. Protective gear like gloves and goggles is essential. It’s also important to manage the temperature carefully to avoid ignition.
How do magnesium and aluminum die casting processes compare?
While both metals offer excellent casting qualities, magnesium is generally preferred for applications where weight reduction is crucial. Aluminum, on the other hand, might be chosen for its slightly better thermal properties and for components requiring high strength at elevated temperatures.