What Is Lighter: Aluminum or Magnesium?

Understanding the Differences in Weight, Strength, and Applications Between Two Lightweight Metals

In a world that’s constantly pushing for energy efficiency, performance, and sustainability, lightweight metals like aluminum and magnesium have become essential in industries such as aerospace, automotive, electronics, and construction. One of the most frequently asked questions in material engineering is: what is lighter, aluminum or magnesium?

This article explores the weight comparison between aluminum and magnesium, along with a detailed look at their physical properties, applications, and how their differences impact material selection. We’ll also explain why manufacturers around the world trust sasaaluminum for precision aluminum products in lightweight engineering.

The Short Answer: Magnesium Is Lighter Than Aluminum

Yes, magnesium is lighter than aluminum. Magnesium is the lightest structural metal currently available for industrial use.

Here are the basic density values of both metals:

• Magnesium: Approximately 1.74 g/cm³

• Aluminum: Approximately 2.70 g/cm³

That means magnesium is about 35% lighter than aluminum by volume.

However, while magnesium wins in terms of weight, aluminum often provides a better combination of strength, corrosion resistance, cost-effectiveness, and processability—factors that are crucial for most applications.

Why Does Weight Matter in Engineering?

Reducing weight in products offers a wide range of benefits:

• Fuel efficiency in vehicles and aircraft

• Easier handling and assembly in manufacturing

• Faster heat dissipation in electronics

• Improved payload and mobility in aerospace or space applications

• Lower material cost per unit of performance

This is why engineers carefully evaluate the weight-to-strength ratio when selecting materials like aluminum or magnesium.

Magnesium: The Lightest Structural Metal

Key Features of Magnesium

• Density: 1.74 g/cm³

• Melting Point: 650°C

• Strength-to-Weight Ratio: Excellent

• Corrosion Resistance: Poorer than aluminum unless properly treated

• Machinability: High; magnesium is easy to machine and cast

• Cost: Typically more expensive than aluminum

• Flammability: Magnesium is highly flammable in powdered or chip form

Common Applications of Magnesium

• Automotive: Gearbox housings, steering wheels, frames

• Aerospace: Lightweight parts for interior and secondary structural components

• Electronics: Laptop casings, camera bodies, mobile devices

• Sporting Goods: Bicycle frames, tennis rackets, and other weight-sensitive products

Magnesium’s lightness makes it a valuable material for industries where every gram matters—but it often needs surface treatment or alloying for strength and corrosion resistance.

Aluminum: The Lightweight All-Rounder

Key Features of Aluminum

• Density: 2.70 g/cm³

• Melting Point: 660.3°C

• Strength-to-Weight Ratio: Excellent

• Corrosion Resistance: Very good, especially in marine and outdoor settings

• Weldability & Formability: Superior to magnesium

• Cost: More affordable and widely available

• Recyclability: 100% recyclable without degradation

Common Applications of Aluminum

• Aerospace: Wing skins, structural beams, fuselage panels

• Automotive: Engine blocks, body panels, frames

• Construction: Window frames, curtain walls, scaffolding

• Consumer Electronics: Smartphone casings, heat sinks, LED housings

• Packaging: Foils, beverage cans, food trays

Thanks to its versatility, aluminum is one of the most widely used metals on the planet—and a specialty of sasaaluminum, where quality and precision go hand-in-hand.

Strength vs. Weight: Which One Wins?

While magnesium is lighter, aluminum is generally stronger and offers better resistance to stress and deformation. That’s why aluminum alloys like 6061, 7075, and 2024 are often chosen for load-bearing structures.

Some magnesium alloys can achieve impressive strength, but they may suffer from creep (slow deformation) under continuous stress or elevated temperatures, making aluminum a more stable option for structural applications.

Corrosion Resistance: Aluminum Outperforms

One of the key weaknesses of magnesium is its susceptibility to corrosion, especially when exposed to saltwater or humid environments. Without protective coatings or special alloying elements, magnesium components can degrade quickly.

Aluminum, on the other hand, forms a natural oxide layer that protects it from corrosion. Aluminum alloys like 5052 and 6063 offer excellent corrosion resistance and are widely used in marine, coastal, and chemical environments.

sasaaluminum offers corrosion-resistant aluminum plates, bars, and tubes that are ideal for long-term use in challenging conditions.

Cost and Availability

While magnesium is more expensive to produce due to limited mining and refining operations, aluminum is abundant, cost-effective, and available in a wide variety of grades and forms.

This makes aluminum a more economical choice for most industrial applications, particularly when weight savings can be balanced with durability and performance.

Environmental Impact and Sustainability

Both aluminum and magnesium are recyclable. However, aluminum has a well-established global recycling infrastructure, and its recycling requires only 5% of the energy used in primary production.

sasaaluminum is committed to offering sustainable aluminum solutions with a lower environmental footprint, supporting eco-conscious product development.

Summary: Aluminum vs. Magnesium – Which One Should You Choose?