Main-Product

Light metals are metallic elements or alloys characterised by a relatively low density — conventionally defined as a density below 5.0 g/cm³ — combined with a high strength-to-weight ratio. This combination of low weight and structural performance makes them indispensable across aerospace, automotive, construction, electronics, and biomedical industries, wherever weight reduction without loss of mechanical integrity is a primary design requirement.

Definition

A chemical element qualifies as a light metal if it satisfies two conditions:​

1. It exhibits metallic properties (conductivity, malleability, ductility, luster)
2. It has a density of ≤ 4.99 g/cm³

By contrast, heavy metals are defined as those with a density exceeding 5.0 g/cm³, such as iron (7.87 g/cm³), copper (8.96 g/cm³), and lead (11.3 g/cm³).​

Commercially Significant Members

While the light metals group technically encompasses all metallic elements below the 5.0 g/cm³ threshold — including alkali metals (lithium, sodium, potassium) and alkaline earth metals (calcium, beryllium, magnesium) — only three are of primary industrial and structural significance:

Shared Properties

Light metals share a distinctive combination of properties that collectively justify their classification as a group:

• Low density — ranging from 19 to 56% of the density of iron and copper
• High strength-to-weight ratio — enabling structural applications where mass is critical
• Good corrosion resistance — typically through formation of a passive oxide surface layer
• Electrical and thermal conductivity — useful in electrical and heat management applications
• Malleability and machinability — amenable to casting, rolling, extrusion, and machining
• Alloying versatility — easily combined with other elements to tailor mechanical properties

Distinction from Related Metal Groups

Industrial Applications

Light metals and their alloys are critical structural materials across multiple sectors:

• Aerospace & aviation — airframes, engine components, structural panels (aluminium, titanium, magnesium alloys)
• Automotive — body panels, engine blocks, wheels, gearboxes (aluminium, magnesium)
• Packaging — beverage cans, foil, food containers (aluminium)
• Construction — window frames, curtain walling, roofing (aluminium)
• Medical devices — implants, prosthetics, surgical instruments (titanium)
• Electronics — casings, heat sinks, battery technology (aluminium, magnesium, lithium)
• Energy storage — lithium-ion batteries for EVs and grid storage (lithium)

References

1. Godden A., Metal Men Recycling (Jun 30, 2020). What Are The Five Groups Of Metals? (Periodic Table Edition)
2. Wikipedia. Metals (pagge version Feb 20, 2026)