About materials used to build cars.

Traditionally steel of arious qualities were used in much of the frame, transmission, motor, suspension and body structures of cars. Steel is still used extensivly in structures that need to be hard, rigid and at the same time somewhat elastic, especially in the mooving mechanics of the car.

It is also used extensively in the whole body of cheaper cars, just because the material is cheep. Steel is however fairly heavy and it is subject to easy chemical corrotion. Therefore steel is steadily moore exchanged for lighter materials that are ressistant to corrotion.

Aluminum, sometimes alloyed with other elements, gain ground as building material in all parts of the car that do not take part as components in dynamic mechanics. Modern motor blocks is very often casted in aluminium. Aluminium is also extensively used in passive, but rigid parts of the car body. It is also typically used in structures with the purpose of protect the driver and vital parts of the car, like bumpers and deformation zones. Since aluminum is difficult to form and need a cellular construction to be rigid and lightweight at the same time. making parts of aluminum is more expensive than forming steel parts. That factor has hindered the becically cheep material aluminum from being even more used.

For structures that need to be absolutely rigid and resistant against friction, ceramic materials, essetially synthetic stone, is used. The inner coating of the motor cylinders, sometimes greater parts of the motor block and parts of breaks are typically made of such materials-

For outer structures that need to be strong against mechanical impacts and corrotion, but do not need to be rigid, plastic or composites are chosen in modern cars. A plastic is a synthetic organic material with a fibrous structure. A composite is typically a mesh of a mechanically resistant material like steel or glass fibres inside a cast of plastic. The outer parts of bumpers and outer protective couting is usually made of plastic or composites.

Plastic is also extensively used in the interior of cars, but in more extensive cars more noble materials like leather and finer fabric is used, at least on the surfaces.

It seems perhaps strange, but many interior details, like the dashboard. is often made of paper mass. That is because paper mass has the right rigidity and strength, but will deform in a favourable way by a collition. The paper material has however protectiopn against damage from water.