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Not knowing the differences between magnesium and aluminum can lead to bad material choices. Both have their own special properties which impact their cost and behavior. This post will cover their differences and practical use cases so you can make better decision for your next task.
Magnesium vs. Aluminum _ Overview
Magnesium and aluminum are two lightweight structural metals and each has its own advantages in industrial applications. Aluminum gives natural resistance against corrosion through its oxide layer while magnesium has electromagnetic shielding capabilities and vibration dampening. Also magnesium is the lightest structural metal, 33% lighter than aluminum.
1. Physical Properties
Density and Weight
Aluminum has a density of 2.70 g/cm³. So it is a lightweight metal but strong enough for most mechanical and structural applications, while magnesium has a lower density of 1.74 g/cm³ and is 34% lighter than aluminum.
Melting and Boiling Points
Aluminum has a boiling point of 2519°C and melting point of 660°C and needs greater processing temperatures. While in contrast, magnesium has boiling point of 1090 °C and melting point of 650 °C which is much lower than aluminum.
2. Mechanical Properties
Strength and Stiffness
Aluminum alloys have a tensile strength of 70–700 MPa and magnesium alloys have tensile strengths of 120-420 MPa. Some variants of magnesium like cast and wrought have tensile strengths of 280 MPa and 360 MPa. Moreover, magnesium has lower stiffness with modulus of elasticity of 45 GPa as compared to aluminium which has 68-70 GPa elasticity.
Strength-to-Weight Ratio
Magnesium has higher strength-to-weight ratio (158 kN·m/kg) than aluminum (130 kN·m/kg). Although aluminum has more absolute strength, magnesium’s lighter weight makes it better in weight critical structural applications.
Corrosion Resistance
Aluminum forms a 5-10 nm inert oxide layer naturally that protects against environmental corrosion. Except saltwater, this self-healing barrier makes aluminum corrosion resistant in most environments. On the other hand, magnesium is more reactive and needs particular surface treatments or coatings to avoid corrosion, especially in saline or humid situations.
Machinability and Formability
Aluminum is machinable but can form gummy buildup because of its soft nature and low melting point. It needs sharp tools and fast cutting speed for better performance. Magnesium, on the other side, is machinable with lower cutting forces and generates less tool wear but requires special handling for fire safety.
Aluminum provides outstanding plastic deformation abilities while magnesium has poor plasticity at room temp and needs to be heated above 250°C for forming.
3. Thermal and Electrical Conductivity
Aluminum has thermal conductivity of 237 W/m·K and an electrical conductivity of 37.7 MS/m. In contrast, magnesium has lower but still good enough thermal conductivity value of 156 W/m·K and an electrical conductivity of 22 MS/m. This is due to aluminum’s more dense atomic structure and magnesium’s hexagonal crystal structure.
4. Applications
Magnesium and aluminum are both used across many industries like:
Aerospace Industry
Aluminum is broadly used in aerospace for up to 80% of aircraft structures, particularly in the construction of wing parts and fuselage components.
Magnesium is used in electronic housings, helicopter transmission casings and engine frames where its lower density is important for weight reduction.
Electronics and Consumer Goods
Aluminum is used to make computer cases, LED lighting frames and heat sinks. On the other side, magnesium is used in smartphone frames, laptop chassis and camera bodies for EMI shielding and heat dissipation. Both metals enable ultra-thin device designs with robust protection.
Construction and Architecture
Aluminum is used in making windows, roofing systems, facades and structural frames with 80+ years service life. In contrast, magnesium is used in prefabricated panels, formwork systems and modular construction elements, there it gives outstanding strength-to-weight ratio for rapid assembly applications.
Packaging Industry
Because of its high corrosion resistance and formability, aluminum is used in food packaging, aerosol cans and beverage containers.
While magnesium has limited packaging applications due to reactivity concerns, mainly used in high-end equipment containers and special protective cases.
Automotive Industry
Aluminum is preferred for making chassis components, radiators, engine blocks, body panels and wheels. But magnesium is used in steering wheels, transmission cases, instrument panel structures and seat frames.
5. Cost Considerations
Currently magnesium ingots are trading between $2,000 and $3,000 per ton, while aluminum price range is between $1,600 and $2,874 per ton in global market. Although magnesium is more expensive, its strength-to-weight ratio can justify the cost in weight critical applications.
6. Environmental Impact and Sustainability
- Aluminum recycling needs only 5% of the energy of original alumninum production and its better recycling infrastructure can further decrease CO2 emissions to 0.6 kg/kg of material.
- Magnesium parts have better environmental behavior in automotive applications and they decrease global warming by 40% compared to aluminum.
Both metals are infinitely recyclable but magnesium recycling needs a special procedure involving solid-state extrusion and aqueous washing.
How to choose between magnesium and aluminum for your project?
Consider weight, corrosion exposure and operating temperature. When you have corrosive situations and high heat applications (of more than 200 °C), you should pick aluminum. But if operating temperature is below 150 °C and reducing weight is your preference then choose magnesium.
To Sum Up
Both aluminum and magnesium have their peculiar industrial uses. Aluminum is best for structural applications (because of better corrosion resistance) and magnesium is better when weight reduction is a priority.
Should you need any kind of metal fabrication or machining service related to aluminium or magnesium then RICHCONN is your best option. We are here 24/7, feel free to contact us anytime.
FAQs
Is magnesium stronger than aluminum?
Aluminum alloys have greater tensile strength (70-700 MPa) than magnesium (120-420 MPa). But magnesium has better specific strength because of lower density.
Which is lighter aluminum or magnesium?
Magnesium has a density of 1.74 g/cm³. So it is 34% lighter than aluminum (2.70 g/cm³) which makes magnesium the lightest structural metal available for commercial use.
Is magnesium a ferrous metal?
No, magnesium is a non-ferrous metal. It belongs to alkaline earth metals group and has no iron in its composition.
