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Material Selection and Production Methods. Robert Love, Venkat Jayaraman July 8, 2008 SSTP Seminar – Lecture 5. Overview. Topics: Basic Material, Properties, Production Polymers Metals Ceramics Composites Material Selection Discussion Activity. Examples: PET, ABS, PVC, PETE
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Material Selection and Production Methods Robert Love, Venkat Jayaraman July 8, 2008 SSTP Seminar – Lecture 5
Overview • Topics: Basic Material, Properties, Production • Polymers • Metals • Ceramics • Composites • Material Selection • Discussion • Activity UF Flight Controls Lab
Examples: PET, ABS, PVC, PETE Polymer – A large molecule of repeating structural units connected by covalent bonds Wide variety of applications Structural and non structural Mass-manufactured and one off Polymers - Introduction Polypropylene Application areas of polymers
Electrical insulation since non-conducting Toughness to resist mechanical abuse such as impact Vibration attenuation Low weight Ease of manufacture Ease of transportation and installation Polymers – Properties and Classification Classification based on properties Fiber Elastomer Plastic
Elastomers – Class of polymers which return to their original shape after the applied stress is removed. Vulcanization – Curing process of rubber involving high heat and formation of cross links with sulfur Elastomer
Thermoplastics – Soften on heating and harden on cooling Individual strands Can be remoulded after heating Thermosets – Polymers are crosslinked Cant melt Thermosets are generally harder, more rigid and more brittle, and their mechanical properties are not heat sensitive Plastics
Mechanical properties comparison Stress Strain Comparison
Polymer Production • Common-Injection Molding, Thin Films UF Flight Controls Lab
Metals • Examples: • Steel, Aluminum, Magnesium, Gold, Zinc, Silver, Platinum, Alloys, Superalloys • Molecular Structure • Metallic Bonding: “Sea of electrons” • Crystal Lattice • Applications • Electronics, Structures, Jewelry UF Flight Controls Lab
Properties of Metals • Electrical • High conductivity, low resistivity • Heat • Excellent conductors, high melting point • Structural • Heavy, fairly to very strong, ductile/malleable, may be strengthened by cold work or heat treatment or annealed to reduce strength • Corrosion • Some highly reactive, some very non-reactive, some radioactive UF Flight Controls Lab
Metal Production UF Flight Controls Lab
Metal Production • Physical Vapor Deposition, Chemical Vapor Deposition, E-Beam Lithography w/Photoresist UF Flight Controls Lab
Ceramics • Examples • Silicon Carbide (SiC), Silica (SiO2), TiC , PZT, Fe3O4, ZnO • Structure • Ionic or Covalent Bonding • Formed by heat addition • Generally metal+nonmetal • Applications • High temperature shields, brake pads, pottery, knives, coatings, electronics UF Flight Controls Lab
Properties of Ceramics • Electronic • Insulators (some exceptions:piezoelectrics PZT), Semi-conductors, superconductivity • Heat • Low conductivity, high melting point • Structural • Heavy, brittle, very strong, low impact resistance (toughness), stiff, high hardness • Corrosion • Generally very unreactive, highly scratch resistant UF Flight Controls Lab
Ceramic Production • Particles->Slurry->Casting, Hand/Kiln (Sintering) UF Flight Controls Lab
Composites • Examples • Concrete, Polymer Matrix + Carbon/Glass/Kevlar fiber • Structure • Matrix + Reinforcement • Combo of 2 of previous 3 material classifications • Applications • Pressure Chambers, Bikes, Aircraft UF Flight Controls Lab
Properties of Composites • IT DEPENDS!!! • Electrical • Usually insulators, some intentionally made conductive • Heat • Generally heat resistant, depends on matrix • Structural • Tailor made strength properties (weight reduction), high stiffness and strength to weight ratio • Corrosion • May have issues UF Flight Controls Lab
Composite Production • Basic Sequence: • By hand: Layup (wet or prepreg) on mold/tool, Vacuum Bag, Bake, Release • May have automatic-tape/winding machines UF Flight Controls Lab
Material Selection UF Flight Controls Lab
Activity • Think of a need and a product • What material(s) do you need? • What are important properties to consider in the material selection process? • How will you make this product? UF Flight Controls Lab