Composite material

A composite is a special material made by combining two or more different parts.

These parts have very different physical or chemical properties. When they are merged, they create a new structure with unique traits. These new traits are often better than the parts alone. For example, a composite might be lighter or much stronger. Inside the finished structure, the original parts stay separate and distinct. This makes a composite different from a simple mixture or a solid solution.

Most engineered composites work using a two-part system. One part is called the matrix, which acts as a binding agent or glue.

The second part is the filler, which gives the material its substance. Fillers can be tiny particles or long, thin fibers. In fiberglass, small glass fibers are embedded in a plastic material. The glass is very stiff and strong, but it can be brittle. The plastic is flexible and ductile, but it is also weak. Together, they make a material that is strong, stiff, and flexible.

People have been using composites for thousands of years. The earliest ones were simple bricks made of mud and straw. Ancient Egyptian tomb paintings even show people making these bricks.

Around 3400 BC, the Ancient Mesopotamians made plywood. They did this by gluing pieces of wood at different angles. This made the wood stronger than it was in nature. Much later, in 1935, Al Simison and Arthur D. Little created the first artificial fiber-reinforced plastic. They used glass fibers and bakelite at the Owens Corning Company.

There are many different types of composites used today. Concrete is the most common artificial composite in the world.

About 7.5 billion cubic meters of concrete are made every single year. It uses cement as a matrix and stones as a filler. To help it resist being stretched, builders add steel bars to make reinforced concrete. Other advanced versions use carbon fiber or aramid fibers. Some special composites even have a "shape memory." This means they can be heated to change shape and then stay strong at lower temperatures.

We see composites in many parts of our modern lives. They are used to build boat hulls, racing car bodies, and even swimming pools. Large airplanes like the Boeing 787 use many composite parts for their wings and bodies.

Spacecraft also rely on carbon composites for heat shields and solar panels. You might even use them without knowing it. They are used in fishing rods, baseball bats, and many hockey sticks. Even your car tires are a type of composite called a particulate composite.