What are the Unique Advantages of Lightweight Metals?

A light metal is a metal that has a relatively low density; the first seven metals in the periodic table, which include lithium, beryllium, sodium, magnesium, aluminum, potassium, and calcium, are collectively known as the “lightest metals.”

In this regard, aluminum and magnesium are commonly used to reduce the weight of components and structures.

Although not one of the seven lightest metals, titanium has a relatively lower density than heavy metals; therefore, it also qualifies as a lightweight metal and has specific industry applications.

Below, we discuss the unique properties of the most commonly used light metals and their specific industry applications.

Unique Properties and Applications of Lightweight Metals

Light metals are commonly used in many industrial applications because of their unique chemical, physical, and mechanical properties. Let’s take a look at some of the most commercially-utilized light metals.

Lithium

Lithium is the lightest metal, with an atomic mass of 6.941 u and the lowest density of 0.534 g/cm³. It has a shiny appearance and is easy to cut, even with a simple knife, when sufficient force is applied.

This extremely light weight metal rapidly oxidizes in free air at room temperature but behaves the opposite at higher temperatures above 572°F.

Lithium is commonly used in the following:

• Ion batteries: Lithium-ion batteries are renowned for their high energy density and efficiency, making them ideal for portable electronics and electric vehicles.
• Glass and ceramics: Lithium compounds are used to enhance the strength and thermal shock resistance of glass and ceramics.
• Medications: Lithium salts are used in psychiatric medications to treat mood disorders.
• Lubricating greases: Lithium-based greases provide superior performance under high-temperature and high-load conditions.
• Aerospace alloys: Lithium-aluminum alloys offer a combination of low density and high strength, crucial for aerospace applications.

Lithium-aluminum alloys are also extensively used for aerospace applications.

Aluminum

Aluminum has a low density of 2.7 g/cm³ and is thus a lightweight metal. It is three times lighter than steel yet has much higher strength-to-weight ratios.

Aluminum is highly corrosion-resistant, as it forms a thin layer of oxide around its surface that prevents further air and water contact. Aluminum conductors weigh only 30% of copper conductors but have double the electrical conductivity for the same electrical resistance compared to other metals.

Different alloying elements such as zinc, copper, and magnesium are added to commercially pure aluminum to enhance its strength further. Aluminum alloys are available in seven different series, engineered to meet unique application requirements.

Al Series	Primary Alloying element(s)	Properties	Applications
1xxx series	99% pure aluminum	High corrosion resistance, workability, and thermal and electrical conductivity	Electrical transmission lines
2xxx series	Copper	Strength and toughness	Aerospace applications
3xxx series	Manganese	Good weldability and machinability	General purpose, beverage cans
4xxx series	Silicon	Low melting point, high ductility	Welding wire, brazing fillers
5xxx series	Magnesium	High strength, high corrosion resistance, and excellent formability, machinability, and weldability	Pressure vessels, marine applications
6xxx series	Magnesium and silicon	Heat treatable, highly formable, good machinability	Aircraft, marine frames, semiconductor assemblies
7xxx series	Zinc	Strongest of all of the series, heat treatable	Aircraft, aerospace, sporting equipment

For fabricators, machinists, and welders, aluminum’s properties offer several advantages:

• Ease of machining: Aluminum’s softness and workability make it easy to cut and shape using various machining techniques.
• Excellent corrosion resistance: Aluminum’s natural oxide layer provides excellent corrosion resistance, making it suitable for various environments.
• Thermal conductivity: Aluminum’s high thermal conductivity makes it ideal for heat exchangers and other applications requiring efficient heat dissipation.
• Versatility: Aluminum is used in a wide range of applications, from aircraft structures and automotive parts to consumer electronics and household items

Magnesium

Magnesium has the lowest mass among the alloys used for die casting. Adding different elements improves magnesium’s mechanical properties and corrosion resistance without compromising its lightweight properties.

Magnesium alloys are 30% less dense than aluminum, with a density of 1.7-2.0 g/cm³. Because of its abundant supply in nature, magnesium excels as the lightest metallic construction material and has a low cost of production.

Therefore, modern aerospace and automotive industries extensively use magnesium alloys to achieve low-cost, lightweight metal designs.

Magnesium is commonly used in the following:

• Sporting goods: Magnesium’s lightweight nature makes it ideal for high-performance sporting equipment like bicycle frames and tennis rackets.
• Automotive applications: Magnesium alloys are used in engine blocks, transmission cases, and other components to reduce vehicle weight and improve fuel efficiency.
• Aerospace industry: Magnesium’s high specific strength makes it suitable for aircraft engine and gearbox casings.
• Biomedical industry: Magnesium’s biocompatibility and biodegradability are being explored for medical implants and devices.

Titanium Alloys

Next to aluminum, titanium offers an excellent strength-to-weight ratio. Although titanium has a higher density than aluminum, it requires less material to achieve the same strength.

The tensile strength of titanium alloys can reach up to 160 ksi, which is twice that of aluminum alloys. Titanium is as strong as steel but weighs only 56% as much. When alloyed with traces of other light metals, titanium achieves even greater strength and workability.

Titanium alloys can be classified into several commercially pure grades and alloy grades based on strength, corrosion resistance, and high-temperature service. For example, titanium bronze metal powders are used in resin casting (cold casting), decorative coatings, and powder metallurgy to achieve excellent stress relaxation resistance.

Certain titanium alloys retain their strength and ductility even at cryogenic temperatures. For instance, Al25Zn alloys with titanium additives display excellent gamma-ray and neutron-shielding properties.

However, titanium alloys come with a high price tag, which can be challenging for those with strict budgets. Titanium is a highly reactive light metal and spontaneously forms a protective hard oxide layer when it comes into contact with oxygen underwater or in free air.

Titanium is commonly used in the following:

• Jet engines
• Medical implants
• Sports equipment
• Bicycle frames
• Missiles
• Spacecrafts
• Powerplant pipes

Challenges with Light Metals

Although there are many advantages to using lightweight metals, there are some downfalls as well. Below, we discuss some of the challenges of using lightweight metals, including machining difficulties and high material costs.

Machining Difficulty

Parts deformation is a significant concern when machining lightweight metals. It is imperative to maintain a distortion-free work holding that gives rigidity to fragile and delicate materials. Metals like titanium require a lower cutting resistance through pulse cutting technology to avoid distortion due to high thermal loads.

The high thermal conductivity of some light metals, like aluminum, can also pose challenges, necessitating the use of specialized cooling techniques to maintain dimensional accuracy and surface finish.

High Material Cost

Using lightweight alloys in the manufacturing process increases project costs, as many of these alloys can be quite expensive. To offset these costs, it’s worth considering utilizing verified metal remnants to obtain the desired characteristics of your end product but at a lower manufacturing cost.

Lightweight metal alloys, such as titanium and magnesium, are particularly costly due to their processing and alloying requirements. Although their high strength to weight ratio makes them valuable, their cost can be a barrier for budget-conscious projects.

Material Waste

A lack of experience and high-end cutting tools can lead to generating metal waste while machining extremely lightweight metals. This, in turn, can result in over-purchasing and exceeding your production budget in the long run.

In the absence of expertise and state-of-the-art cutting equipment, it is better to partner with a local metal supplier to get your light metals cut to size on time.

Precision-Cut Lightweight Metals in the Bay Area and Beyond

Industrial Metal Service has been serving as a trusted metal supplier and recycler of light alloys and a wide range of other metal alloys in the San Francisco Bay Area for more than two decades. Our wide inventory includes aluminum, steel, titanium, and copper, as well as specialty metals such as Invar.

We supply new metals sourced straight from U.S. mills as well as verified metal remnants for those looking to lower their costs while maintaining high quality for their production runs. Our other services include precision metal sawing, machine teardown, and warehouse cleanup.

Choosing the right metal can sometimes be overwhelming, but we can help. Give us a call to discuss your metal requirements. We look forward to working with you.