Thermal conductivity of aluminium – when is it crucial?

Aluminium and heat – a special material

Aluminium is one of the metals with the highest thermal conductivity. This makes it a preferred material in many technical applications where targeted heat dissipation or distribution is required. Particularly in the form of sheets, plates and solid cut pieces, this physical advantage plays a central role. At the same time, however, the high conductivity also places demands on design and processing.

In addition, aluminium scores with its low density, high corrosion resistance and good formability. This combination makes it ideal for applications in which both mechanical stability and thermal management are required. From electronics to mechanical engineering, from vehicle construction to building services: aluminium offers versatile application possibilities wherever temperature conditions must be reliably controlled.

Technical values: how well aluminium conducts heat

The thermal conductivity of pure aluminium is around 235 W/m·K. This means that aluminium can transport heat very efficiently – significantly better than many other engineering materials.

Comparison with other materials

Material	Thermal conductivity (W/m·K)
Pure aluminium	approx. 235
Copper	approx. 390–400
Stainless steel	approx. 15–20
Steel (unalloyed)	approx. 45–50
PVC (plastic)	approx. 0.15

Although copper offers even better conductivity, aluminium is far more widespread in everyday technical use due to its favourable ratio of weight, price and conductivity.

Differences between alloys

Thermal conductivity depends heavily on the respective alloy. Pure aluminium (e.g. EN AW-1050A) has the highest values. Alloys with a higher proportion of alloying elements such as magnesium, copper or silicon (e.g. EN AW-5754, EN AW-6082) sometimes exhibit significantly lower values, but are still far above classic structural steels.

When is thermal conductivity decisive in practice?

Heat sinks, heat sinks & passive cooling

A classic application is the design of passive cooling systems. Aluminium sheets serve here as carriers for electronic components or as a base for cooling fins. The large surface area of an aluminium sheet enables the efficient distribution and dissipation of the waste heat generated.

Enclosures with integrated heat dissipation

In many devices and machines, a separate cooling solution is not possible. Here, aluminium enclosures are actively used for heat dissipation. The material conducts the heat from the interior to the enclosure surface, where it is released via convection or radiation.

Machine cladding with temperature requirements

When cladding machines or control cabinets, heat generation inside can become a problem. Aluminium sheets help to reduce the temperature inside the enclosure without the need for ventilation slots or active fans. This is a decisive advantage, particularly in closed systems or in sensitive environments (e.g. food industry, medical technology).

Aluminium sheets with high thermal conductivity: what matters?

Sheet type, alloy, thickness

Not every aluminium sheet conducts heat equally well. The decisive factors are:

• The alloy: pure aluminium (e.g. EN AW-1050A) is ideal for high conductivity.
• The thickness: the thicker the sheet, the more heat it can absorb and release.
• The surface: a larger surface improves heat release to the environment.

Processing without thermal bridges

During assembly, attention should be paid to full-surface contact with heat-generating components. Insulating materials, paint layers or air gaps massively reduce effective heat conduction. Screw connections, clamps or bonding should be designed in such a way that they do not restrict thermal conductivity.

The choice of suitable thermal pastes or interlayers is also particularly important when perfect surface pressure is not possible. Even minor unevenness or components that do not lie flat can worsen heat dissipation many times over. The choice of fastening elements and their tightening torque also influences how well the heat is transferred. Anyone who takes these points into account during design and assembly gets the maximum out of the good conductivity of aluminium.

Conclusion: use heat properly – or avoid it

The thermal conductivity of aluminium is a decisive factor in many industrial applications. It can be used in a targeted way to dissipate heat, solve temperature problems or even avoid additional cooling systems. The decisive factors are the choice of the right alloy, sheet thickness and a well-thought-out overall concept for heat dissipation. Anyone who uses aluminium sheets in a targeted way can not only achieve technical advantages, but also save costs and weight.