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ablation
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The erosion or vaporization of material from causes like abrasion and heat. Parts made from carbon-carbon composites are resistant to ablation.
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advanced composite
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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.
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alloy
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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.
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aluminum
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A ductile metal used in metal matrix composites.
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ambient temperature
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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.
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aramid
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An advanced composite material made from nylon. Aramid fiber reinforcements are strong and flexible.
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aromatic chemical
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A highly stable type of chemical used in thermoplastic resins. Aromatic chemicals often have a strong odor.
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autoclave
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A pressure vessel that promotes faster curing through a combination of vacuum and heat. Advanced composites often require autoclave curing.
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borides
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Boron-based compounds used to create ceramic matrices for advanced composites.
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boron
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A semi-metallic chemical element used in advanced composite reinforcements. Boron fibers are much stronger than carbon fibers or glass fibers.
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brittleness
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The measure of a material's tendency to fracture from being drawn, stretched, or formed. As the rigidity of a material increases, brittleness increases.
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carbides
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Carbon-based compounds used to create ceramic matrices for advanced composites.
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carbon
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A non-metallic chemical element used in advanced composite reinforcements and matrices. Carbon is very strong and has high resistance to heat.
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carbon fiber
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A high-strength, high-modulus reinforcement used in advanced composites. Carbon fibers may be mixed with a carbon matrix to form carbon-carbon composites.
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carbon-carbon composite
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A composite made from carbon fibers and a carbon matrix. Carbon-carbon composites have the best heat resistance of any composite material.
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ceramic
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A hard, brittle material that can withstand high temperatures and resist corrosion. Some advanced composite matrices are made from ceramic materials.
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ceramic matrix composite
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A highly specialized advanced composite often used for aerospace applications. CMCs are stiff, lightweight, and can withstand extremely high temperatures.
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C-glass
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A type of glass fiber that provides greater resistance to chemicals. A small portion of advanced composites use C-glass.
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char
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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.
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continuous
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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.
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copper
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A ductile, thermally and electrically conductive metal used in metal matrix composites.
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cure time
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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.
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degassing
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Removing dissolved gases from a liquid. Volatile gases and trapped air must be removed from metal matrix composites through degassing.
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discontinuous
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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.
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ductility
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The ability of metal to be drawn, stretched, and deformed without breaking.
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elasticity
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The measure of a material's ability to return to its original shape after being deformed from stress.
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environmental properties
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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.
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epoxy resin
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A tough, heat-resistant resin used in advanced composites. Boron fibers are typically applied to a tape that has been preimpregnated with epoxy resin.
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ether
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An organic compound found in polyetheretherketone.
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fiber
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A slender, thread-like reinforcing material used in composites. Fibers are larger than whiskers.
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fiberglass
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Reinforcement material made from extremely fine strands of glass. Fiberglass is the most commonly used reinforcement material in composites.
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fiberglass reinforced plastics
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A commercial composite made from fiberglass and polyester resin.
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flammability
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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.
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glass transition temperature
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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.
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ketone
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An organic compound found in polyetheretherketone.
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magnesium
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A strong, lightweight metal used in metal matrix composites.
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matrix
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The material that binds together the reinforcing fibers of a composite. Advanced composites use specially formulated polymers, ceramics, and carbons as the matrix.
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mechanical properties
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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.
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metal
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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.
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metal matrix composite
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A composite made from a metallic matrix and high-performance reinforcements. MMCs have high levels of strength, stiffness, and relatively high resistance to heat.
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metalloid
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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.
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modulus
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The stiffness of a material. Carbon fiber reinforcements have a high modulus.
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nickel
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A corrosion-resistant metal used in metal matrix composites.
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nitrides
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Nitrogen-based compounds used to create ceramic matrices for advanced composites.
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nylon
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A thermoplastic polymer used to make aramid fibers for advanced composites. Nylon is strong and very flexible.
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organic compound
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A highly stable type of chemical that always contains carbon. Many polymers used in composites are organic compounds.
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organic resin
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A resin made from carbon-based materials. Phenolic resin is an example of an organic resin.
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oxidation
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A chemical reaction involving the addition of oxygen and the loss of electrons. Oxidation causes metal to rust.
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oxides
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Oxygen-based compounds used to create ceramic matrices for advanced composites.
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particle
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A very tiny piece of material used as a reinforcement in advanced composites.
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phenolics
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A group of thermoset polymers derived from phenol. Phenolics are often used to create carbon resins.
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plasma environment
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An environment of partially ionized gas. A plasma environment is extremely disruptive to electrical equipment.
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polyester resin
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The most widely used thermoset polymer in the composite industry. Fiberglass reinforced plastics are made with unsaturated polyester and fiberglass reinforcement.
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polyetheretherketone
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PEEK. An advanced thermoplastic polymer used extensively in the aerospace, automotive, and marine industries.
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polymer
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A long chain of very large molecules made up of many atoms. Polymers are used to make thermoplastic resins for composites.
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polymer matrix composite
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A composite made from a polymer resin. Polymer matrix composites are not as strong or heat-resistant as metal matrix and ceramic matrix composites.
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polyphenylene sulfide
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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.
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preform
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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.
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prepreg
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A ready-to-mold sheet of fiber reinforcement that has been preimpregnated with resin. A prepreg made with boron fibers is very stiff.
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radiation
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Energy emitted in the form of particles or waves. Prolonged exposure to radiation can damage composites.
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reinforcement
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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.
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S-glass
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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.
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silicon carbide
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A chemical compound made of up carbon and silicon. Silicon carbide is used to make high-performance reinforcements and matrices for composites.
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solvent
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A substance that dissolves another substance.
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space debris
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Natural and man-made objects found beyond the earth's atmosphere. Space debris can strike and damage a space vehicle.
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strength
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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.
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tensile stress
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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.
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thermal properties
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The characteristics of a material that determine how it reacts when it is subjected to excessive heat, or heat fluctuations over time.
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thermoplastic
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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.
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thermoset
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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.
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titanium
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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.
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toughness
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The measure of the composite's ability to absorb mechanical forces before it breaks. Tough materials generally have some measure of elasticity.
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traditional composite
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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.
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vacuum environment
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An environment with very low density and pressure, such as outer space. In a vacuum, heat cannot be transferred through convection.
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warpage
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The deformation of a part after molding. Parts made with polyphenylene sulfide resins are vulnerable to warpage.
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wet-out
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The condition of being completely covered, and filled, with resin. Thermoplastic resins allow for good fiber wet-out in composites.
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whisker
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A very thin, short filament. Whiskers are smaller than chopped fibers.
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