Intermediate Mechanics of Materials: Properties, Classification, and Applications, Slides of Mechanics of Materials

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MAE 343 Intermediate Mechanics of Materials Docsity.com Materials Science Properties Composition Microstructure Processing Docsity.com Classes of Property Economic Price and availability Recyclability General Physical Density Mechanical Modulus Yield and tensile strength Hardness Fracture toughness Fatigue strength Creep strength Damping Thermal Thermal conductivity Specific heat Thermal expansion coefficient Electrical and Magnetic Resistivity Dielectric constant Magnetic permeability Environmental Interaction Oxidation Corrosion Wear Production Ease of Manufacture Joining Finishing Aesthetic Color Texture Feel Docsity.com Metals • Metals are typically split into ferrous (iron containing) and non-ferrous • Most widely used metals are alloys except for aluminum and precious metals • Metals are in general are good thermal and electrical conductors. Many metals are relatively strong and ductile at room temperature, and many maintain good strength even at high temperature. 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 Aluminum (Aluminium) • Aluminium or aluminum is a silvery and ductile member of the poor metal group of chemical elements. It has the symbol Al; its atomic number is 13. • Aluminium is found primarily in bauxite ore and is remarkable for its ability to resist corrosion (due to the phenomenon of passivation) and its light weight. Structural components made from aluminium and its alloys are vital to the aerospace industry and very important in other areas of transportation and building. Although aluminium is the most abundant metallic element in Earth's crust (believed to be 7.5% to 8.1%), it is very rare in its free form, occurring in oxygen-deficient environments such as volcanic mud, and it was once considered a precious metal more valuable than gold. Napoleon III, Emperor of France, is reputed to have given a banquet where the most honoured guests were given aluminium utensils, while the other guests had to make do with gold ones. 20th century metallurgists developed improved processes for extraction. Docsity.com Aluminum 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 What is a Ceramic? • Solid compounds formed by heat or heat and pressure that contain – At least one metal and one non-metal or one non- metal elemental solid (NMES) [MgO, Al2O3, YBa2Cu3O7] – At least two NMES [SiC] – At least two NMES and a non-metal Docsity.com My name is Bond….. • In ceramics bonding is a mixture of ionic and covalent • If ionic bonding dominates crystal structures occur that are typically based on FCC and HCP • If covalent bonding dominates rings and tetrahedral units are often seen Docsity.com TABLE 3.4 Relationship between silicate structure and the O/Si ratio No. of oxygens per Si Structure O/Si ratio Bridg. _Non-bridg. Structure and examples 2.00 4.0 0.0 Three-dimensional network Quartz, tridymite, cristabolite are all polymorphs of silica 2.50 3.0 1,0 Infinite sheets Na2Si205 Clays (Kaolinite) 2.75 2.5 1,5 Double chains, og, asbestos 3.00 2.0 20 Chains (Si03)2"", Na,SiO;, MgSiO Repeat unit (Si03)°~ AN A 4.90 00 40 Isolated SiO}, tetrahedra MgqSi0, olivine, 1Si04 7 LigSiO4 Gplest way to determine the number of nonbridsi be number of Si atoms in the repeat unit. Figure 3.1 Some common ceramic structures: (d/) rock salt, (b) cesium chloride, (2) zine blende, id) wurtzite, (e) calcium fluorite, (f) rutile. ‘gens per Si is to divide the charge on the rep, Docsity.com Conformation of Polymers Amorphous thermoplastic Semi-crystalline thermoplastic Crosslinked thermoset Docsity.com PA PE PP UP-GF PBT+PC PVC ABS PPO PBT ABS+PC POM OTHERS PMMA PUR Plastics use in BMW 5 Series Docsity.com Elastomers • Entropy springs • Lightly crosslinked • Typically non-linear elastic (a) (b) (c) Docsity.com Composite Materials Carbon fiber reinforced epoxy crossply laminate Silicon carbide particulate reinforced aluminum Silicon carbide monofilament reinforced glass ceramic After D. Hull and T. W. Clyne, “An introduction to composite materials”, 2nd Edition, Cambridge University Press, Cambridge, (1996) Polymer matrix composite (PMC) Metal matrix composite (MMC) Ceramic matrix composite (CMC) Docsity.com L] Toughened Graphite [) Graphite \ Hybrid Fiberglass \ _— —