Mendeleev.com · Objects

What is an aluminium can made of?

A drinks can looks simple, but body, lid and inner coating have different jobs.

Layer by layer

Can body

Usually an aluminium alloy rather than pure aluminium; manganese and magnesium can improve strength and forming behaviour.

Lid and tab

The top needs different mechanical properties and commonly uses a different aluminium alloy from the body.

Inner coating

A very thin polymer coating separates the drink from the metal and helps protect flavour and container.

A can is therefore not one uniform piece of pure aluminium. Alloy design and coatings let a very small amount of material do several different jobs.

Why combine materials?

Real products rarely ask one material to do everything. Strength, corrosion resistance, thermal behaviour, appearance, cost and manufacturing can point to different choices, so layers and alloys are often more useful than a single pure substance.

Why this object uses several materials

Most manufactured objects solve several problems at once: strength, electrical conduction, thermal behaviour, corrosion resistance, weight, appearance and cost. One pure material rarely satisfies all of them.

That is why a useful way to read an object is part by part. Each component reveals a different compromise between chemistry, physics and engineering.

Look at the mechanism, not just the object

A useful way to understand an everyday object is to follow a chain: what enters the system, which material or component responds, what physical or chemical change occurs, and what useful effect comes out. This separates the scientific principle from the casing and design.

The same principle often appears in very different objects. Once the mechanism is recognised, links between chemistry, materials, electricity, heat and mechanics become much easier to see.

01The alloy must be light and formable

02A thin internal coating matters chemically

03Recycling saves the metal but not every layer intact

The alloy must be light and formable

Pure aluminium is too soft for many can requirements. Alloying plus work hardening gives enough strength while preserving the ductility needed for deep drawing and wall ironing.

A thin internal coating matters chemically

Acidic or salty drinks should not remain in direct contact with bare aluminium for long periods. A food-compatible polymer layer reduces corrosion and unwanted metal–drink reactions.

Recycling saves the metal but not every layer intact

Remelting recovers aluminium efficiently; paints, lacquers and contaminants are removed or destroyed during processing. The recycled metal is then composition-controlled for new products.

Worked example

Why can a very thin aluminium can still resist internal pressure?

Its cylindrical shape carries pressure efficiently, while alloy strength and work hardening let a thin wall withstand the load.

Common traps to avoid

A can is not simply pure aluminium with no coatings.
Recycling does not mean the original coating survives into the new can.