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Unformatted text preview: Materials Science and Engineering &amp;#2; Composition means the chemical make-up of a material. &amp;#2; Structure means a description of the arrangements of atoms or ions in a material. &amp;#2; Synthesis is the process by which materials are made from naturally occurring or other chemicals. &amp;#2; Processing means different ways for shaping materials into useful components or changing their properties Metals and Alloys Gray cast iron Automobile engine blocks Castable, machinable, vibration damping ceramics and Glasses SiO2-Na2O-CaO Window glass Optically transparent,thermally insulating Polymers Polyethylene Food packaging Easily formed into thin,flexible, airtight film Polymerization occurs when small molecules, combine to produce larger molecules, or polymers. Functional Classification of Materials e Aerospace e Biomedical/ r Electronic Materials/ r Energy Technology and Environmental Technology r Magnetic Materials/ Photonic or Optical Materials /r Smart Materials r Structural Materials A Crystalline material is a material comprised of one or many crystals. e Each crystal, atoms or ions show a long-range periodic arrangement. r Single crystal is a crystalline material made of a SINGLE Crystal, it means it has no grain boundaries r Polycrystal is a crystalline material comprised of many crystals r Grain boundaries are regions between grains of a polycrystalline material. In chemistry, mineralogy, r Ductility refers to the ability of materials to be stretched or bent without breaking r Glass temperature is a temperature above which many polymers and inorganic glasses no longer behave as brittle materials r Intermetallic compound is a compound such as Al3V formed by two or more metallic atoms Covalent bonding requires that electrons be shared between atoms in such a way that each atom has its outer sp orbital filled. In silicon, with a valence of four, four covalent bonds must be formed An ionic bond is created between two unlike atoms with different electronegativities. Describe the ionic bonding between magnesium and Chlorine The electronic structures and valences are: Mg: 1 s 22 s 22 p 6 3 s 2 valence = 2 Cl: 1 s 22 s 22 p 6 3 s 23 p 5 valence = 7 Fraction of covalent exp[-0.25(3.5 - 1.8)2] when O=1.8 and sl=3.5 Interatomic spacing is the equilibrium spacing between the centers of two atoms. r Binding energy is the energy required to separate two atoms from their equilibrium spacing to an infinite distance apart. r Modulus of elasticity is the slope of the stress-strain curve in the elastic region (E). r Yield strength is the level of stress above which a material begins to show permanent deformation....
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This note was uploaded on 11/17/2010 for the course MECT 27982 taught by Professor Franciscorobles-hernandez during the Fall '10 term at The School of the Art Institute of Chicago.
- Fall '10