| ablation |
The erosion or vaporization of material from causes like abrasion and heat. Parts made from carbon-carbon composites are resistant to ablation. |
| advanced composite |
A composite made from specially formulated resins and high performance fibers. Advanced composites are used for applications that require a customized mixture of resins and reinforcements to produce specific properties in the composite. |
| alloy |
A metal consisting of a mix of two or more elements, one of which must be a metal. Alloys can be used to make metal matrix composites. |
| aluminum |
A ductile metal used in metal matrix composites. |
| ambient temperature |
The nominal temperature of the air that surrounds devices and systems. Suppliers of composite materials usually recommend a maximum ambient temperature in which the part can function. |
| aramid |
An advanced composite material made from nylon. Aramid fiber reinforcements are strong and flexible. |
| aromatic chemical |
A highly stable type of chemical used in thermoplastic resins. Aromatic chemicals often have a strong odor. |
| autoclave |
A pressure vessel that promotes faster curing through a combination of vacuum and heat. Advanced composites often require autoclave curing. |
| borides |
Boron-based compounds used to create ceramic matrices for advanced composites. |
| boron |
A semi-metallic chemical element used in advanced composite reinforcements. Boron fibers are much stronger than carbon fibers or glass fibers. |
| brittleness |
The measure of a material's tendency to fracture from being drawn, stretched, or formed. As the rigidity of a material increases, brittleness increases. |
| carbides |
Carbon-based compounds used to create ceramic matrices for advanced composites. |
| carbon |
A non-metallic chemical element used in advanced composite reinforcements and matrices. Carbon is very strong and has high resistance to heat. |
| carbon fiber |
A high-strength, high-modulus reinforcement used in advanced composites. Carbon fibers may be mixed with a carbon matrix to form carbon-carbon composites. |
| carbon-carbon composite |
A composite made from carbon fibers and a carbon matrix. Carbon-carbon composites have the best heat resistance of any composite material. |
| ceramic |
A hard, brittle material that can withstand high temperatures and resist corrosion. Some advanced composite matrices are made from ceramic materials. |
| ceramic matrix composite |
A highly specialized advanced composite often used for aerospace applications. CMCs are stiff, lightweight, and can withstand extremely high temperatures. |
| C-glass |
A type of glass fiber that provides greater resistance to chemicals. A small portion of advanced composites use C-glass. |
| char |
A type of material that is formed from burning plastic in a low-oxygen environment. Carbon matrices are created from the carbon-containing char of polymer-based resins such as phenolics. |
| continuous |
Covering the entire dimension of a part without a break or interruption. Continuous fibers provide greater strength but are more expensive to integrate with the matrix. |
| copper |
A ductile, thermally and electrically conductive metal used in metal matrix composites. |
| cure time |
The amount of time it takes for the molecules in a composite to cross-link. Longer cure times increase the cost of making the composite and the possibility of something going wrong in the curing process. |
| degassing |
Removing dissolved gases from a liquid. Volatile gases and trapped air must be removed from metal matrix composites through degassing. |
| discontinuous |
Characterized by being chopped or cut into small pieces. In ceramic matrix composites, whiskers tend to have the best mechanical properties of the discontinuous reinforcements. |
| ductility |
The ability of metal to be drawn, stretched, and deformed without breaking. |
| elasticity |
The measure of a material's ability to return to its original shape after being deformed from stress. |
| environmental properties |
The characteristics of a material that determine how it reacts to other phenomena in close proximity. Environmental factors that affect a material include noise, air quality, machine vibration, moisture, and temperature, among other factors. |
| epoxy resin |
A tough, heat-resistant resin used in advanced composites. Boron fibers are typically applied to a tape that has been preimpregnated with epoxy resin. |
| ether |
An organic compound found in polyetheretherketone. |
| fiber |
A slender, thread-like reinforcing material used in composites. Fibers are larger than whiskers. |
| fiberglass |
Reinforcement material made from extremely fine strands of glass. Fiberglass is the most commonly used reinforcement material in composites. |
| fiberglass reinforced plastics |
A commercial composite made from fiberglass and polyester resin. |
| flammability |
The characteristics of a material the determine its ability or tendency to ignite or burn when exposed to an open flame. Some advanced composite applications require materials with low flammability. |
| glass transition temperature |
The point at which a rigid solid becomes pliable and can be formed, shaped, or molded. In general, a higher Tg allows for greater thermal stability and helps to prevent defects during the curing of a part. |
| ketone |
An organic compound found in polyetheretherketone. |
| magnesium |
A strong, lightweight metal used in metal matrix composites. |
| matrix |
The material that binds together the reinforcing fibers of a composite. Advanced composites use specially formulated polymers, ceramics, and carbons as the matrix. |
| mechanical properties |
The characteristics of a material that determine how it reacts when it is subjected to a force that attempts to stretch, dent, scratch, or break it. |
| metal |
A naturally occurring material with high electric and thermal conductivity, luster, density, and strength. Some advanced composite matrices are made from metals and metal alloys. |
| metal matrix composite |
A composite made from a metallic matrix and high-performance reinforcements. MMCs have high levels of strength, stiffness, and relatively high resistance to heat. |
| metalloid |
An element that has the qualities of both a metal and a non-metal. Boron is a metalloid that shares some of the qualities of aluminum, silicon, and carbon. |
| modulus |
The stiffness of a material. Carbon fiber reinforcements have a high modulus. |
| nickel |
A corrosion-resistant metal used in metal matrix composites. |
| nitrides |
Nitrogen-based compounds used to create ceramic matrices for advanced composites. |
| nylon |
A thermoplastic polymer used to make aramid fibers for advanced composites. Nylon is strong and very flexible. |
| organic compound |
A highly stable type of chemical that always contains carbon. Many polymers used in composites are organic compounds. |
| organic resin |
A resin made from carbon-based materials. Phenolic resin is an example of an organic resin. |
| oxidation |
A chemical reaction involving the addition of oxygen and the loss of electrons. Oxidation causes metal to rust. |
| oxides |
Oxygen-based compounds used to create ceramic matrices for advanced composites. |
| particle |
A very tiny piece of material used as a reinforcement in advanced composites. |
| phenolics |
A group of thermoset polymers derived from phenol. Phenolics are often used to create carbon resins. |
| plasma environment |
An environment of partially ionized gas. A plasma environment is extremely disruptive to electrical equipment. |
| polyester resin |
The most widely used thermoset polymer in the composite industry. Fiberglass reinforced plastics are made with unsaturated polyester and fiberglass reinforcement. |
| polyetheretherketone |
PEEK. An advanced thermoplastic polymer used extensively in the aerospace, automotive, and marine industries. |
| polymer |
A long chain of very large molecules made up of many atoms. Polymers are used to make thermoplastic resins for composites. |
| polymer matrix composite |
A composite made from a polymer resin. Polymer matrix composites are not as strong or heat-resistant as metal matrix and ceramic matrix composites. |
| polyphenylene sulfide |
PPS. An advanced thermoplastic resin that can withstand relatively high temperatures. PPS is flame retardant and has good resistance to chemicals, mildew, sunlight, and abrasion. |
| preform |
A tough but flexible fiberglass structure that is roughly the same shape as the final product. The powdered matrix of a CMC is made into a preform which is heated and then formed into a composite part. |
| prepreg |
A ready-to-mold sheet of fiber reinforcement that has been preimpregnated with resin. A prepreg made with boron fibers is very stiff. |
| radiation |
Energy emitted in the form of particles or waves. Prolonged exposure to radiation can damage composites. |
| reinforcement |
The part of the composite that provides strength, stiffness, and the ability to carry a load. The reinforcement material used in advanced composites is often a high-performance fiber. |
| S-glass |
A type of glass fiber that provides greater strength and can withstand higher temperatures than E-glass. Advanced composites are more likely to use S-glass. |
| silicon carbide |
A chemical compound made of up carbon and silicon. Silicon carbide is used to make high-performance reinforcements and matrices for composites. |
| solvent |
A substance that dissolves another substance. |
| space debris |
Natural and man-made objects found beyond the earth's atmosphere. Space debris can strike and damage a space vehicle. |
| strength |
The measure of a material's ability to carry a load. When selecting materials for advanced composites, manufacturers must know the strength of the material. |
| tensile stress |
The internal load that a part is subjected to when pulled apart by an applied force. Carbon fiber reinforcements can withstand a high amount of tensile stress. |
| thermal properties |
The characteristics of a material that determine how it reacts when it is subjected to excessive heat, or heat fluctuations over time. |
| thermoplastic |
A polymer composed of molecules that are not cross-linked, or are cross-linked to a weaker degree. Thermoplastics can be melted and hardened repeatedly without changing their chemical structure. |
| thermoset |
A polymer that cannot be re-melted or reformed once it has cured. Thermosets have higher rigidity and better thermal stability than thermoplastics, but they take longer to process. |
| titanium |
Ti. A silvery white "space age" metal with a high strength-to-weight ratio, excellent flexibility, and exceptional corrosion resistance. Titanium can be a component of metal matrix composites and is commonly used in medical components and in aerospace applications. |
| toughness |
The measure of the composite's ability to absorb mechanical forces before it breaks. Tough materials generally have some measure of elasticity. |
| traditional composite |
A composite that uses a relatively consistent combination of polymer resin and fiberglass reinforcement. Traditional composites are low-cost and are processed by traditional methods. |
| vacuum environment |
An environment with very low density and pressure, such as outer space. In a vacuum, heat cannot be transferred through convection. |
| warpage |
The deformation of a part after molding. Parts made with polyphenylene sulfide resins are vulnerable to warpage. |
| wet-out |
The condition of being completely covered, and filled, with resin. Thermoplastic resins allow for good fiber wet-out in composites. |
| whisker |
A very thin, short filament. Whiskers are smaller than chopped fibers. |