They can withstand extreme heat, like in the nozzle cone of a rocket and in a space capsule's heat shield. Perhaps the best known use of carbon-carbon composites is the black nose cone on the space shuttle. Currently, carbon-carbon materials are used in a component separate from the main structure of the space shuttle. NASA Langley scientists are working to integrate it into the structure, thereby saving weight. I and Indy race cars where they have replaced asbestos linings.
Metals make up another materials group, specifically aluminum lithium and improved titanium alloys.
It doesn't crack easily and can be repaired if dented. It can tolerate a great deal of strain before it fails. The new metals are an improvement over other aluminum alloys. In addition to being stronger and stiffer, they are lighter weight which means vehicles can have smaller engines, carry less fuel and fly longer. NASA Langley's goal is to make them more cost effective.