carbon fiber, a material consisting of graphite fibers in a plastic matrix. The properties of carbon fibers include high stiffness, high tensile strength, low weight, high chemical resistance, high temperature tolerance, and low thermal expansion. Carbon fibers are usually combined with other materials to form a composite. When combined with graphite to form carbon-carbon composites, it has a very high heat tolerance. It is used in radiological devices to reduce patient exposure to x-rays.
