Composites Terminology Flashcards
Reinforcement
Fibers, particles, etc
Matrix
Continuous, form-filling medium that encapsulates the reinforcement
Composite
Multiphase material consisting of >= 2 distinct phases
MMC
Metal matrix composite:
Metal matrix is aluminum, tungstun, titanium, etc.
Reinforcement is particles or short fibers such as silicon carbide, alumina, boron, carbon fiber.
Advantages of MMC
Wear resistance, higher service temperature, strength to weight, impact strength, thermal or electrical advantages (for stealth)
CMC
Ceramic matrix composites.
Ceramic Matrix: Boron nitride, silicon carbide, tungston carbide
Reinforcement: typically particles or short fibers like silicon carbide, alumina, boron, carbon fiber
Advantages of CMC
Temperature resistance, chemical/corrosion resistance, fatigue/impact improvements, weight, ballistic protection
PMC
Polymer matrix composites.
Polymer matrix: epoxy, polyester, cynate ester, phenolics, thermoplastics
Reinforcements: Fiber or fabric like fiberglass, carbon aramids (kevlar/twaron), polyethylene (UHMWPE)
Advantages of PMC
Strength to weight (aerospace), potential cost improvements, ease of process, safety (energy dissipation on impact)
Role of reinforcement in composites
Structural reinforcement
Material carrier
Carries stress (long fiber and fabric)
Redirects stress (short fiber and particles)
Tough
Weight savings
Contributes to electrical, thermal properties
Rule of mixtures
Ec=EmVm+ErVr
E is modulus and V is volume fraction
Role of matrix in composites
Holds fibers in place Barrier to environment Transfers stress (broken long fibers or short fibers) Toughness Controls shear strength Huge role in electrical, thermal, and stealth properties Dictates manufact. process Cosmetic appearance of part
