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Light Metals: Definition, Properties, Uses, and Types

Xomety X
By Team Xometry
April 18, 2024
 13 min read
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Light metals are best known for their low-density or low-weight characteristic features. Despite their light weight, they boast impressive strength, and this has formed the basis of their wide application across numerous industries. 

From the aerospace industry to the construction industry, light metals are used to create sturdy yet lightweight structures. Their use is more crucial whenever weight reduction is required while still maintaining structural integrity. The common lightweight metals include: aluminum, magnesium, and titanium.

In this article, we will talk about what light metals are all about, their properties, uses, and types, as well as their wide application across diverse industries.

What Is Light Metal?

A light metal is a metal characterized by its low density (even less than the density of steel, which is about 7.8g/cm3) and high strength-to-weight composition. Light metals are generally lightweight, malleable, ductile, and corrosion-resistant. They are mainly derived from the earth’s crust and have been further harnessed for their distinct properties. 

The common light metals include: aluminum, magnesium, and titanium. These metals are extensively used in numerous industries, including: transportation, construction, aerospace, and automation. They have high strength and are remarkably resilient, hence why their use keeps pushing the boundaries of innovations.

What Are the Different Properties of Light Metals?

The different properties of light metals include:

1. Low Density 

Density is defined as the mass per volume unit of material. Light metals are of low densities, which means they have a low mass relative to volume compared to heavier metals like steel or iron. 

This property makes them advantageous in weight-sensitive applications as it enables the production of lightweight components for various structures or machines in numerous industries. This usually results in improved fuel efficiency, higher payload capacity, and increased maneuverability of the structures that these lightweight components are used in. 

Light metals are used in various applications because of their low densities, such as: the production of seating structures, overhead bins, and cabin panels for aircraft in the aerospace industry. They may, however, require additional reinforcement in certain applications to support the weight.

2. High Thermal Conductivity 

Thermal conductivity refers to the ability of a material to conduct heat. Light metals possess high thermal conductivity, which means they can transfer heat across themselves efficiently. This property prevents their overheating and allows for efficient heat management, whenever significant heat is involved.

They are highly valuable in applications in which heat dissipation is critical, such as: electronic devices, heat exchangers, and cooling systems. Although they can be susceptible to deformation at very high temperatures and may even require thermal insulation in certain applications, they are highly reliable as thermal conductors and have shown increased thermal performance over time.

3. Excellent Electrical Conductivity 

Electrical conductivity denotes the ability of a material to conduct electrical current. Light metals are widely known for exhibiting excellent electrical conductivity. This makes them essential in electrical and electronic applications, and they can be used in various aspects of wiring and power transmission in an electronic device, as well as in the production of electronic components. 

With excellent electrical conductivity, light metals ensure efficient transmission of electricity, which minimizes energy loss and enhances the performance of electrical and electronic systems.

4. Malleability and Ductility 

Light metals are both malleable and ductile, which means that they can be rolled into thin sheets without breaking (malleable) or stretched into wires without fracturing (ductile). This property allows them to be easily formed into various shapes and designs.

Light metals have found wide use in manufacturing processes such as: forging, stamping, and extrusion because of this property. It makes light metals highly versatile and able to form intricate designs. They are, however, susceptible to deformation during the forming process, which puts them at a disadvantage as other processes may be necessary to restore their properties.

5. Corrosion Resistance 

Corrosion resistance is the ability of a material to withstand degradation when exposed to moisture or chemicals. Light metals exhibit excellent corrosion-resistance properties, and this makes them suitable for outdoor applications and in places more susceptible to moisture exposure.

Corrosion resistance ensures the longevity and durability of light metals. It reduces their maintenance costs and extends the service life of the components and structures they are used in.

Is a Base Metal Categorized as a Light Metal?

No, a base metal is not categorized as a light metal. Base metals are metals that oxidize or corrode easily when exposed to air or moisture. This is in contrast with the light metals that are more corrosion-resistant and can survive being exposed to moisture or harsh chemicals.

Common examples of base metals include: copper, iron, nickel, and zinc.

What Is the Use of Light Metals?

The use of light metals spans numerous industries which include:

  1. Construction of aircraft structures like: wings, fuselages, and empennages in the aerospace industry.
  2. Construction of steering wheels, engine blocks, transmission cases, exhaust systems, and valve springs in the automotive industry.
  3. Manufacture of components of smartphones, tablets, and laptops in consumer electronics.
  4. Manufacture of sports equipment like bicycles and recreational vehicles in the sports industry.
  5. Manufacture of medical devices like dental implants and bone plates in the medical industry.
  6. Construction of hulls for boats in the marine industry.
  7. Manufacture of armored vehicles, naval vessels, and military aircraft in defense and military.

What Are the Different Types of Light Metals?

The different types of light metals include:

1. Magnesium

Magnesium (Mg) is a silvery-white alkaline earth metal and one of the commonly available light metals. It is widely employed in the aerospace, automotive, and electronic industries because of its high strength-to-weight ratio and excellent electrical conductivity. It is also used in flares and fireworks due to the bright white light it produces when burned. It is, however, highly reactive and readily prone to corrosion, which can limit its use in areas in which exposure to corrosive substances cannot be avoided.

2. Potassium

Potassium (K) is an alkali metal and also one of the most common light metals available. It is a soft, silvery-white metal that is primarily used in fertilizers for plant growth, as a heat transfer medium, and in various chemical processes for chemical synthesis. It is of low density, which is a characteristic feature of all light metals. However, it is highly reactive with water and air. 

3. Aluminum

Aluminum (Al) is also a silvery-white, non-magnetic light metal with a characteristic soft feature. It is lightweight, corrosion-resistant, and has excellent thermal conductivity. It is widely applicable in various industries, including: transportation, construction, and electrical industries, for the production of beverage cans, automotive parts, window frames, and electrical wires. It is environment-friendly as it is easily recyclable. It, however, requires high energy consumption to extract and process.

4. Lithium

Of all light metals, Lithium (Li) is the lightest metal and the least dense solid element. It is also a soft, silvery-white alkali metal and is purposefully used in rechargeable lithium-ion batteries for electronic devices, electric vehicles, and energy storage systems. It is highly reactive and flammable, thus posing a potential safety concern due to its reactivity.

5. Sodium

Sodium (Na) is a highly reactive light metal that reacts with air and water and is less dense than water. It is primarily used in chemical synthesis, as a heat transfer fluid and other heat transfer applications, and in sodium-vapor lamps. Sodium compounds are used in detergents, food preservatives, and industrial processes.

6. Titanium

Titanium is a lustrous transition metal with the symbol Ti. It has a silver color, is of low density, and stands out for its excellent strength-to-weight ratio. Titanium is corrosion-resistant and biocompatible and, thus, is widely used in: aerospace applications, medical implants, marine equipment, and sports equipment.

7. Calcium

Calcium (Ca) is one of the light metals that is an alkaline earth metal. It is a characteristic soft, silvery-white metal that is less reactive than other alkaline earth metals. It is widely used in steel production, as a reducing agent in metal refining, and in the manufacture of calcium compounds. It also serves as an essential nutrient for living organisms. It, however, has limited applications compared to other light metals.

8. Beryllium

Beryllium (Be) is a relatively rare light metal. It is lightweight and has a high melting point. It is widely used in aerospace, defense, and electronics industries due to its thermal conductivity and dimensional stability. It is toxic in its metallic form, a cause for safety concerns with its use. Beryllium alloys are commonly used in: aerospace components, satellite structures, and electronic connectors.

How To Choose Which Type of Light Metals To Use?

To choose the appropriate light metal for a particular application, certain factors and requirements need to be considered. The following steps can guide your choice of the type of light metal to use:

  1. Determine the application requirements of the light metal. You need to consider the mechanical, thermal, and electrical properties of the intended application of the light metal. You also need to be well aware of the immediate operating environment of the light metal.
  2. Properly assess the individual properties of the light metal in relation to the application requirement.
  3. Factor in the cost of procuring each light metal, including the cost of raw material, processing, fabrication, and finishing, and see if it aligns with the budget set aside for the project.
  4. You also need to consider the environmental impacts of each light metal throughout its life cycle, its extraction phase, through its ready-for-use phase.
  5. You can also consult the expertise of material engineers regarding light metals and their applications.

What Type of Light Metal Is Used in Aerospace Manufacturing?

Titanium is the light metal of choice preferred in aerospace manufacturing. This is primarily due to the excellent combination of its properties that are critical for aerospace applications. Titanium offers a high strength-to-weight ratio, which makes it ideal for the manufacture of lightweight aerospace components. Its strength also allows it to withstand high stress and extreme operating conditions experienced in aerospace environments. 

Additionally, titanium exhibits excellent corrosion resistance, which is important for withstanding the harsh conditions of aerospace environments, including: high altitudes, wide temperature variations, and exposure to moisture and corrosive substances.

What Type of Light Metal Is Used in Automotive Manufacturing?

In automotive manufacturing, aluminum is the light metal used due to the array of excellent properties that it possesses. Aluminum offers a high strength-to-weight ratio, which reduces the overall weight of vehicles without compromising structural integrity. This also results in better fuel economy and lower emissions, making the vehicles more eco-friendly and also meeting the regulatory requirements for increased fuel-efficiency standards. 

Aluminum is also corrosion-resistant, which makes it suitable for use in various automotive components, including: body panels, engine blocks, and suspension parts, contributing to the longevity and durability of vehicles.

What Is the Lightest Metal?

Lithium is the lightest metal known, and it is the least dense solid element. Lithium's lightweight nature is due to its low atomic mass and density. It has a density of only about 0.534 grams per cubic centimeter (g/cm³), which makes it significantly less dense than other metals, including aluminum and magnesium. 

What Is the Advantage of Using Light Metals?

The advantages of using light metals include:

  1. Are low weight, which is widely used in vehicles for improved fuel efficiency, in aerospace for increased payload capacity, and in sports equipment for enhanced maneuverability.
  2. Possess excellent strength-to-weight ratios. This makes them suitable for applications in which strength and durability are essential while weight needs to be minimal, such as in aircraft structures and automotive components.
  3. Are highly corrosion-resistant, which makes them ideal for use in areas of exposure to moisture, chemicals, or saltwater to extend the life span of components and prevent degradability.
  4. Have high thermal conductivity, which allows them to transfer heat efficiently. This property makes for their wide use in heat exchangers, cooling systems, and electronic devices for optimal performance and the safety of these devices.
  5. Possess high electrical conductivity and are essential materials for electrical wiring, connectors, and components in electronics, power transmission, and renewable-energy systems. 
  6. The use of light metals garners environmental benefits such as reduced greenhouse gas emissions and energy consumption, which protects the atmosphere from contaminants. Also, many light metals are recyclable, allowing for the conservation of resources and the reduction of waste.

What Is the Disadvantage of Using Light Metals?

The disadvantages of using light metals include:

  1. The cost of procuring some light metals, such as titanium and magnesium, can be significantly more expensive than traditional metals like steel or iron, and this increased cost has led to their limited widespread adoption.
  2. Some light metals, such as lithium and beryllium, are not readily available in nature, which may result in potential supply constraints.
  3. Light metals, such as magnesium and lithium, are highly reactive and prone to corrosion when exposed to moisture, oxygen, or corrosive environments. This affects the durability and longevity of the components that they are used in.
  4. Some light metals can pose fire hazards as they have the potential to ignite and burn vigorously when exposed to heat or oxygen, leading to safety concerns in numerous applications.

What Is the Difference Between Light Metals and Non-Ferrous Metals?

Light metals are metals that have low densities relative to other metals. They are typically lightweight and have relatively low atomic numbers. Examples of light metals include: aluminum, magnesium, titanium, and lithium. 

Non-ferrous metals, on the other hand, are metals that do not contain iron as the primary element. They lack significant amounts of iron in their composition. Examples of non-ferrous metals include: aluminum, copper, zinc, lead, tin, gold, and silver. 

All light metals are also non-ferrous, as they do not contain iron as their primary element. A typical example of this is aluminum.

To learn more, see our full guide on Non-Ferrous Metals.

What Is the Difference Between Light Metals and Heavy Metals?

Light metals are metals that have low densities, low atomic mass, and low atomic weight. They are lightweight. Examples include: aluminum, magnesium, and titanium.

Heavy metals, however, are metals that have high densities, high atomic mass, and high atomic weight compared to other metals. Examples include: mercury, lead, chromium, and nickel.

Summary

This article presented light metals, explained what they are, and discussed their properties and uses. To learn more about light metals, contact a Xometry representative.

Xometry provides a wide range of manufacturing capabilities and other value-added services for all of your prototyping and production needs. Visit our website to learn more or to request a free, no-obligation quote.

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Xomety X
Team Xometry
This article was written by various Xometry contributors. Xometry is a leading resource on manufacturing with CNC machining, sheet metal fabrication, 3D printing, injection molding, urethane casting, and more.