Aluminum is the lightest metal

Metals and alloys whose density is less than 5 g / cm³ are generally defined as light metals. A light metal is characterized by a relatively high strength and a relatively low weight. Technical light metals required in large quantities are aluminum, titanium and magnesium. Lithium and beryllium are used in rather small amounts.

The economically most important users of light metals are in addition to the automotive industry, aerospace and construction - and the trend is rising. In addition to pure light metals and light metal alloys, composite materials are also often used here.

Light metal processing

Although light metals can be machined and processed in many areas just like all other metals, due to their plastic deformability and mechanical strength, some special features must be taken into account. This is especially true with regard to various joining techniques such as gluing, welding, screwing, riveting and surface coating. In the course of scientific and technical progress and modern processing options, light metal processing is also becoming increasingly important. Light metal constructions and light metal construction methods are increasingly helping to save energy and thus protect the environment.

The most important light metals and their properties


The basis of aluminum production is bauxite, which is the third most common element in the earth's crust after oxygen and silicon. The light metal aluminum has a comparatively low density, very good electrical conductivity and corrosion resistance. In addition, it can be processed mechanically very well. Aluminum can be hardened and shows no steep drop in terms of its notched impact strength. The light metal is almost completely recyclable. Surfaces made of aluminum can be made very decorative. The disadvantage is the very high energy requirement in the extraction of bauxite and the production of aluminum. Compared to steel, the light metal aluminum has a significantly lower strength. In addition, it is more expensive on the world market than structural steel or simple plastics.

Read more about aluminum in Materials technology script for aluminum.


Magnesium is the lightest metal of all and is mainly used in aircraft and automobile construction. It has a very low density and is extremely easy to cast, harden and machine. The recyclability of magnesium is around 100 percent. In contrast to most other light metals, magnesium is susceptible to corrosion. In addition, it has a lower strength and rigidity compared to aluminum. Magnesium is difficult to cold-form and its weldability is considered problematic. When machining magnesium parts, special precautions are necessary because very fine and, above all, flammable chips are produced.


Titanium is a comparatively heavy light metal. Titanium ore is mainly mined in the USA, Canada, Scandinavia and Australia. The advantage of titanium is its low density and, at the same time, very high strength. In addition, titanium is insensitive to corrosion. However, due to the high cost of extraction and processing, titanium is very expensive. Because it is also difficult to machine or otherwise process, all items and components made of titanium are very cost-intensive.


The light metal beryllium is mainly used in aerospace technology, reactor technology and medical technology. In addition to its low density, it has a particularly high rigidity and can therefore only be formed using special processes. Beryllium components are very expensive. Beryllium dust is poisonous, so special safety precautions must be taken during processing.