Materials Science: Classification & Properties of Metals, Polymers, Ceramics, & Composites, Slides of Classical Mechanics

Download Materials Science: Classification & Properties of Metals, Polymers, Ceramics, & Composites and more Slides Classical Mechanics in PDF only on Docsity! Metals Polymers Ceramics Composites Classification of Materials Docsity.com Classes of Materials • Metals – Iron and Steels – Aluminum and Alloys – Copper and Alloys – Nickel and Alloys – Titanium and Alloys • Ceramics and Glasses – Alumina – Magnesia – Silica – Silicon Carbide – Silicon Nitride – Cement and Concrete • Polymers – PE – PMMA – Nylon (PA) – PS – PU – PVC – PET – PEEK – EP – NR • Composites – GFRP – CFRP Docsity.com Iron Iron was the third of the prehistoric materials ages (stone, bronze, iron). Iron began to be used once furnaces could be made hot enough to melt iron. Iron quickly became the metal of choice because of its abundance in the earth’s crust. Iron however has two major problems: 1) Corrosion 2) Brittleness These problems are partially overcome by alloying iron to make steel Docsity.com Steel Steel is an alloy consisting mostly of iron, with a carbon content between 0.02% and 1.7 or 2.04% by weight (C:1000– 10,8.67Fe), depending on grade. Carbon is the most cost-effective alloying material for iron, but various other alloying elements are used such as manganese and tungsten.[1] Carbon and other elements act as a hardening agent, preventing dislocations in the iron atom crystal lattice from sliding past one another. Varying the amount of alloying elements and form of their presence in the steel (solute elements, precipitated phase) controls qualities such as the hardness, ductility, and tensile strength of the resulting steel. Steel with increased carbon content can be made harder and stronger than iron, but is also more brittle. The maximum solubility of carbon in iron (in austenite region) is 2.14% by weight, occurring at 1149 °C; higher concentrations of carbon or lower temperatures will produce cementite. Alloys with higher carbon content than this are known as cast iron because of their lower melting point.[1] Docsity.com Steel Docsity.com SuperAlloys • A superalloy, or high-performance alloy, is an alloy able to withstand extreme temperatures that would destroy conventional metals like steel and aluminum. Superalloys exhibit excellent mechanical strength and creep resistance at high temperatures, good surface stability, and corrosion and oxidation resistance. Superalloys typically have an austenitic face-centered cubic crystal structure. A superalloy's base alloying element is usually nickel, cobalt, or nickel-iron. Superalloy development has relied heavily on both chemical and process innovations and has been driven primarily by the aerospace and power industries. Typical applications are in the aerospace industry, eg. for turbine blades for jet engines. • Examples of superalloys are Hastelloy, Inconel, Haynes alloys, Incoloy, MP98T, TMS alloys, and CMSX single crystal alloys. Docsity.com Variety of ceramic applications • Furnace linings, heat sinks, capacitors, fuel cells, magnets (hard and soft), superconductors, windows, optical fibers, nuclear fuel, artificial hip joints, cutting tools, turbine blades, bearings Docsity.com Docsity.com Ceramics: crystalline and glassy Zinc blende (ZnS) structure Continuous random network oxide glass Docsity.com Repeat units of some common polymers CO COO(CH2)2O n CH2CH2 n CHCH2 n CHCH2 n CH3 • Poly(ethylene) • Poly(propylene) • Poly(styrene) • Poly(ethylene- terephtalate) Docsity.com Conformation of Polymers Amorphous thermoplastic Semi-crystalline thermoplastic Crosslinked thermoset Docsity.com Elastomers • Entropy springs • Lightly crosslinked • Typically non-linear elastic (a) (b) (c) Docsity.com The nitrile groups from neighbouring chains, being polar, attract each other and bind the chains together, making ABS stronger than pure polystyrene. The styrene gives the plastic a shiny, impervious surface. The butadiene, a rubbery substance, provides resilience even at low temperatures. ABS can be used between −25 and 60 °C. Production of 1 kg of ABS requires the equivalent of about 2 kg of oil for raw materials and energy. ABS Docsity.com Polycarbonate Although polycarbonate has high impact-resistance, it has low scratch-resistance and so a hard coating is applied to polycarbonate eye-wear lenses. The characteristics of polycarbonate are quite like those of polymethyl methacrylate (PMMA; acrylic), but polycarbonate is stronger and more expensive. This polymer is highly transparent to visible light and has better light transmission characteristics than many kinds of glass. CR-39 is a specific polycarbonate material — although it is usually referred to as CR-39 plastic — with good optical and mechanical properties, frequently used for eyeglass lenses. Docsity.com Spectra® fiber is one of the world’s strongest and lightest fibers. A bright white polyethylene, it is, pound-for-pound, ten times stronger than steel, more durable than polyester and has a specific strength that is 40 percent greater than aramid fiber. Spectra® fiber is made from ultra-high molecular weight polyethylene that is used in a patented gel-spinning process. Polyethylene is a remarkably durable plastic, and scientists at Spectra Technologies have captured the tremendous natural strength in the molecular backbone of this everyday plastic to create one of the world’s strongest and lightest fibers. The gel- spinning process and subsequent drawing steps allow Spectra® fiber to have a much higher melting temperature (150°C or 300°F) than standard polyethylene. With outstanding toughness and extraordinary visco-elactic properties, Spectra® fiber can withstand high-load strain-rate velocities. Light enough to float, it also exhibits high resistance to chemicals, water, and ultraviolet light. It has excellent vibration damping, flex fatigue and internal fiber-friction characteristics, and Spectra® fiber’s low dielectric constant makes it virtually transparent to radar. Spectra® fiber is used in numerous high-performance applications, including police and military ballistic-resistant vests, helmets and armored vehicles, as well as sailcloth, fishing lines, marine cordage, lifting slings, and cut-resistant gloves and apparel. Honeywell also converts Spectra® fiber into the Spectra Shield® family of specialty composites for armor and other applications. Docsity.com Polypropylene Polypropylene is often used as a stronger alternative to polyethylene. Docsity.com a x ax, coldgear- aa LS ES Toughened Graphite CL Graphite Hybrid Fiberglass \ Review • Describe the subject of materials science and engineering. Docsity.com Review • Cite the primary classifications of solid materials. Docsity.com