3 Lightweight Metals and Their Key Benefits Explained

by | Feb 19, 2023 | CNC Machining, Machining Materials

Steel is the most widely used metal in the world today and offers a great balance of material properties at a good cost. But when steel, at a density of 7.8g/cm³, is too heavy for the application, product designers must turn to one of the lighter materials available. While many plastics are available to lighten the load, lightweight metals are a popular and sturdy choice.

The most popular lightweight metals and alloy alternatives to steel are aluminum, titanium, and magnesium. To help designers evaluate these lightweight metals, we’ve created a short guide that compares the benefits and drawbacks of each, along with some common applications.

#1 Titanium – 42% lighter than steel

As an alloy, titanium is the strongest metal on this list by far. It also has excellent corrosion resistance, performs well at high temperatures, and works well for implants thanks to its high biocompatibility. But it does come with a few drawbacks.

Titanium is the heaviest of the three lightweight metals on our list at 4.51g/cm³. It’s also the most expensive and the most challenging to machine. As a result, titanium is often reserved for more demanding applications that require a more robust material.

Common applications for titanium can include:

  • Chemical processing equipment that requires a high chemical resistance.
  • Long-lasting medical implants, devices, and prosthetics.
  • Strong and lightweight aerospace components
  • Corrosion-resistant marine 

#2 Aluminum – 65% lighter than steel

At nearly a third the weight of steel (2.70g/cm³), aluminum is the most widely used non-ferrous metal in the world. Aluminum offers great corrosion resistance, and some alloys can offer strength that approaches that of carbon steel. Despite being more costly than steel, aluminum is cheaper than both magnesium and titanium.

Aluminum offers very high formability and machinability, good weldability, and high ductility. It has both high thermal and electrical conductivity. Despite this, it is susceptible to wear, has a lower strength-to-weight ratio than titanium, and does not perform well at high temperatures. Aluminum and magnesium have similar melting points at 660°C (1220°F) and 650°C (1202°F), respectively

Since it is so widely used, aluminum has a vast number of applications, some of which include:

  • Electronics components and electrical wiring.
  • Heat sinks for efficient heating and cooling
  • Aircraft fuselages and numerous other aerospace components
  • Durable, cost-effective consumer products like furniture and cookware.
  • Architectural elements, such as railings and siding
  • Cast aluminum and extruded aluminum automotive parts

#3 Magnesium – 77% lighter than steel

Crystalised magnesium

CSIRO, CC BY 3.0, via Wikimedia Commons

More expensive than aluminum, but cheaper than titanium alloys, magnesium is used as the base for the lightest structural alloys around. Magnesium on its own is vulnerable to corrosion and chemical degradation, and it also offers a lower strength than the other metals in this article. However, modern magnesium alloys and coating techniques are helping to improve the strength and durability of magnesium products.

Magnesium offers high machinability but is generally only machined by specialist shops willing to accept the danger of highly combustible magnesium dust. It also offers a unique damping ability that makes it useful for mitigating vibrations on sensitive equipment. Most magnesium applications are geared toward taking advantage of its extremely light weight (1.74g/cm³), including:

  • Components of consumer products like luggage, ladders, and cameras
  • High-performance sporting and recreational equipment, like bicycle frames
  • Weight-reducing parts in gear and equipment
  • Performance automotive parts, like magnesium alloy wheels and gearboxes

Selecting the Best Lightweight Metal

Engineer and project manager discussing a design

The three metals discussed in this article are all great ways to save weight on your product. You might consider them if you’re looking to make something that’s more convenient for consumers to hold and use, or looking to improve performance and reduce friction by lowering overall assembly weight. Choosing which one to use ultimately comes down to factors like cost, strength, and durability requirements.

  • Titanium offers exceptional durability but is expensive and challenging to work with.
  • Magnesium is incredibly lightweight, and when alloyed with other elements, can create a stronger metal that still improves performance.
  • Aluminum is the most cost-effective and commonly used non-ferrous alloy, offering very good durability for a large number of applications.

Our machine shops provide professional CNC machining services for titanium and aluminum alloy products, along with a wide range of other metal and non-metal materials. If you’re looking to manufacture lightweight products and need to partner with a cost-effective, quality-focused vendor, contact Gensun today.

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