The 94 naturally occurring elements form millions of chemical compounds with each other - and yet it is sometimes difficult to find the ideal material for an application. The solution may be to combine materials with each other to achieve desired properties: This results in composite materials.
Properties of materials such as density, strength, hardness, thermal expansion, electrical conductivity, thermal conductivity and melting temperature are compared in our experiment "Materials". In the electroplating experiment we examine metals. The requirements for the material we are looking for are good thermal conductivity and high strength. Tungsten has a high strength and melts only at very high temperatures. In contrast, the thermal conductivity of copper is much better.
Setup for the production and testing of our metal-metal composite. Bild: DLR (CC-BY 3.0)
An alloy of tungsten and copper could be the solution, but we will understand why this is not possible. With the help of electric current, we therefore create a copper coating on a tungsten wire and then measure the thermal conductivity of our new metal-metal composite.
Finally, we will examine other composite materials and discuss their advantages and disadvantages. Glass fibre mats can be bonded to aluminium plates, for example, to create an extremely light and very stable material. The majority of the upper shell of the Airbus A 380 is made of this "GLARE". The strength of turbine blades can be increased by so-called TMCs (titanium matrix composites). For this purpose, numerous thin ceramic rods are embedded in a titanium matrix.