Car bodies are made of a number of different materials, from steel to plastic; and usually they are made of more than one material. Manufacturers are continually seeking new materials or composites that are safe and lightweight, leading to better fuel efficiency. Researchers are even working on cars made from biodegradable materials like hemp and corn, though such a car will not be realized until well into the future.
Steel and Cast Iron
Steel and cast iron, strong and durable, have long been the traditional metal for car bodies. Because these metals are heavy, they are used today mainly to reinforce other materials.
Aluminum
Aluminum has the same properties as steel, but is lighter. Because it is much more expensive, it is not used exclusively. Car manufacturers usually use aluminum alloys, combining aluminum with steel and titanium.
Fiberglass
Fiberglass is one of the most commonly used materials in car bodies. Made of fibers of silicon, it is strong, lightweight and inexpensive, and can be combined into composite materials with metals or plastics.
Plastic Composites
Thousands of plastics are used in automobile manufacturing today. For car bodies, manufacturers use composites made up of various plastics, or plastics combined with fiberglass or metals.
Polycarbonates
Since the 1970s, composites made of carbon fibers, called polycarbonates, have been used to make car bodies. Because carbon fiber is lightweight but strong, it is a popular choice for race car bodies.