Liquid crystal an anisotropic uid usually a melt or

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Unformatted text preview: g patt that is located in the interstices of the structure under Matrix on which atoms or ions are placed to form a crystal. consideration. Interstitials may be either the same or a different species than the solvent. lattice point One position in the three-dimensional space-filling repeating pattern that forms a crystal. One interstitial solid solution A solid solution in which Fc more atoms or ions are placed at each lattice point. atoms or ions of a foreign species are located in the (a) interstitial positions. lever rule An equation that enables one to calculate intrinsic conduction Electrical conduction in pure relative amounts of two phases present in a two-phase semiconductors such as Force Ge, and GaAs. Si, mixture in terms of the compositions of the alloy and t Fc = Ff = Fm phases present. invariant reaction A reaction is which there are zero degrees of freedom. line compound A compound whose composition is independent of temperature. ion implantation A process in which ions of light (b) elements such as boron and nitrogen are made to impinge linear density The number of atoms centered on a on the surface of the workpiece at a high velocity. The crystallographic direction per unit length. assume for simplicity that the constituent materials are isotropic. This assumption is surface hardens due to penetration of the ions. liquid crystal An anisotropic fluid, usually a melt or reasonable except when organic fibers are used. ionic bond Asubjected to an axial force Fc , involving Figure 14.5–2a, the total If the composite is type of primary bond as shown in solution characterized by molecular alignment. force is partitioned into two parts, Ff (force on the fibers) and Fm (force on the matrix). electronegative and electropositive atoms that display a liquid metal embrittlement A degradation mechani We may write, significant difference in their electronegativity values in which a liquid metal preferentially attacks the grain Fc Ff (14.5–3) (usually EN Fm 1.7). boundaries in a solid. Noting that F A Equation 14.5–3 The written as: ionic (atomic) ,polarization can be temporary displaceliquidus The temperature at which a liquid begins to (14.5–4) c positive and Am f Af m negative ions in the presence of an ment of Ac freeze during equilibrium cooling conditions. electric f , and where c , field. m are the average normal stresses on the composite, fibers, and matrix long-range order Existence of a regular repeating and Ac , Af , and Am are the corresponding cross-sectional areas. Dividing both sides of ionization potential The energy required to remove an Equation 14.5–4 by Ac yields: arrangement of atoms, ions, or molecules within a electron from an isolated neutral atom. crystalline region of a material. Af Am c f m isomorphousAc Having cthe same structure. When applied (14.5–5) A luminescence Absorption of light or electromagnetic to a phase diagram, indicating that the solid phase has Since for continuous-fiber composites the fiber and matrix area fractions are the same as radiation at high frequencies with subsequent reradiatio the same structure fractions i...
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This note was uploaded on 02/25/2013 for the course PHYS 2202 taught by Professor Sowell during the Spring '10 term at Georgia Institute of Technology.

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