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| a metallic material that is obtained by chemical combinations of different elements, typicall alloys have much better mechanical properties than pure metals |
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| a group of crystalline inorganic materials characterized by good strength, especially in compression and high melting temperatures, many have good electrical and thermal insulation behavior |
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| a group of materials formed from mixtures of metals, ceramics, or polymers in such a manner that unusual combinations of properties are obtained. |
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| the chemical makeup of a material |
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| the arrangment of atoms in a crystalline material |
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| a material comprised of one or many crystals, in each crystal atoms or ions show a long range periodic arrangement |
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| an amorphous material derived from the molten state, typically, but not always based on silica |
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| a special class of materials obtained by forming a glass and then heat treating it to form small crystals. |
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| regions between grains of a polycrystalline material |
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| crystals in a polycrystalline material |
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| properties of a material, such as strength, that describe how well a material withstands applied forces, a materials response to an applied force, microstructure sensitve |
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| describe characteristics such as color, elasticity, electrical or thermal conductivity, magnetism, etc. a material's response to an applied field, not microstructure sensitive |
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| a material comprised of many crystals (as opposed to a material comprised of just one crystal) |
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| a group of materials normally obtained by joining organic molecules into giant molecular chains or networks, characterized by low strength, low melting temperatures and poor electrical conductivity. |
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| a special group of polymers in which molecular chains are entangled, but not interconnected, they can easily be melted and formed into useful shapes, normally they have a chainline structure (eg polyethylene) |
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| a special group of polymers that decompose rather than melt upon heating, they are normally quite brittle due to a relatively rigid 3-D network structure (eg-polyurethane) |
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| polymers that have a higly coiled structure that provides them with the ability to exhibit extreme elastic deformation. |
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| a material that does not have a long range order of atoms (only short range order) |
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| a negatively charged ion produced when an atom, usually of a nonmetal, accepts one or more electrons. |
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| all atoms and their arrangments that constitute the building blocks of matter |
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| The energy required to separate two atoms from their equilibrium spacing to an infinite distance apart, the strength of the bond between two atoms. |
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| a positively charged ion produced when an atom usually a metal gives up its valence electrons |
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| coefficient of thermal expansion (CTE) |
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| The amount by which a material changes its dimesnions when the temperature changes, a material with a low CTE tends to retain its dimesnions when the temperature is changed. |
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| the bond formed between two atoms when the atoms share their valence electrons, a relatively strong primary bond. |
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| materials in which atoms are arranged in a periodic fashion exhibiting a long-range order |
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| the ability of materials to be stretched or bent without breaking |
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| the relative tendancy of an atom to accept an electron and become an anion, strongly electronegative atoms readily accept electrons |
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| the equilibrium spacing between the centers of two atoms. |
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| the bond formed between two different atom species when one atom (the cation) donates its valence electrons to the second atom (the anion), an electrostatic attraction binds the two ions together (relatively strong primary bond) |
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| structures of a material at the macroscopic level (~>1000-10,000 nm), features include things such as porosity, coatings, internal and external microcracks, etc |
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| the electrostatic attraction between the valence electrons and the positively charged ionic cores |
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| structure of a material at a length scale of ~10 - 1000 nm, includes features such as grain size, grain orientation, defects, etc |
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| the slope of the stress strain curve in the elastic region (E), also known as Young's modulus |
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| molecules that have developed a dipole moment by virtue of an internal or external electric field |
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| strong bonds between adjacent atoms resulting form the transfer or sharing of outer orbital electrons |
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| the number of electrons in an atom that participate in bonding or chemical reactions, usually the number of electrons in the outer s and p energy levels |
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| secondary bond developed between atoms and molecules as a result of interactions between dipoles that are induced or permanent |
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| the characterisitic of an element being able to exist in more than one crystal structure depending on temperature and pressure |
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| materials including glass that have no long-range order, or crystal structure |
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| having different properties in different directions |
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| fourteen possible lattices that can be created using lattice points (show location of atoms) |
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| directions in a crystal along which atoms are in contact |
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| the number of nearest neighbors to an atom in its atomic arrangement (speaks to how efficiently packed a unit cell is) |
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| the arrangement of atoms in a material into a regular repeatable lattice |
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| the generic size and shape of a unit cell, include cubic, tetragonal, orthrombic, hexagonal, monoclinic, rhombohedral and triclinic |
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| materials that have long range order (composed of many small grains or crystals) |
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| a microstructural feature representing a disruption in the periodic arrangment of atoms/ions in a crystalline material. |
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| crystallographic directions that all have the same characteristics although their sense is different, generic directions, denoted by < > |
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| a family of materials typically derived from molten inorganic glasses and processed into crystalline materials with very fine grain size and improved mechanical proeprties |
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| solid, non-crystalline materials that have only short range atomic order (amorphous) |
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| small crystal in a polycrystalline material |
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| regions between grains of a polycrystalline material |
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| locations between the normal atoms or ions in a crystal into which another usually different atom or ion is placed, typically the size of the interstitial location is smaller than the atom or ion that is to be introduced |
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| having the same properties in all directions |
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| a collection of points that divide space into smaller equally sized segments |
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| the lengths of sides of the unit cell and the angles between those sides, describe the size and shape of the unit cell |
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| the number of lattice points per unit length along a direction |
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| shorthand notation to describe crystallographic planes and directions |
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| the fraction of a direction or plane that is actually covered by atoms or ions, speaks to how efficiently packed a unit cell is in a direction or on a plane |
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| the number of atoms per unit area whose centers lie on the plane |
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| crystallographic planes that all have the same cahracteristics even though their orientations are different; denoted by { } |
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| material composed of many grains |
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| compounds exhibiting more than one type of crystal structure (similar to allotropic) |
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| the distance from one lattice point to the adjacent lattice point along a direction |
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| the regular and predictable arrangement of atoms over short distances usually one or two atom spacings only |
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| the sequence in which close-packed planes are stacked, if the stacking sequence is ABABABAB a HCP structure is produced, if a stacking sequence of ABCABCABC then an FCC structure is produced |
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| a subdividion of the lattice that still retains the overall cahracteristics of the entire lattice |
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| the direction and distance that a dislocation moves in each step, aka slip vector |
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| critical resolved shear stress |
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| the shear stress required to cause a dislocation to move and cause slip |
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| a change in the slip system of a dislocation |
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| a line imperfection in a crystalline material, movement of dislocations helps explain how a metallic material deforms, interference with the movement of these helps explain how metallic materials are strengthened |
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| dislocation that is made up of an extra "half plane" of atoms, burgers vector is perpendicular to dislocation line |
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| deformation that is fully recovered when the stress causing it is removed, results from the bonds stretching |
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| a pair of pointe defect produced when an ion moves to create an interstitial site leaving behind a vacancy |
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| a surface defect representing the boundary between two grains, the crystal has a different oriention on either side of the grain |
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| point defect produced when an atom is placed into the crystal at a site that is not normally a lattice point |
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| defects such as dislocations in which atoms or ions are missing in a row (1-D) |
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| a dislocation that contains partly edge components and partly screw components |
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| The shear stress, which depends on the Burgers vector and the interplanar spacing , required to cause a dislocation to move |
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| permanent deformation of a material |
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| imperfections such as vacancies that are located typically at one or a few sites in a crystal. |
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| The relationship between shear stress , the applied stress, and the orientation of the slip system |
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| A point defect ionically bonded materials, a stoichiometric number of cation and anion vacancies |
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| a dislocation produced by skewing a crystal so that one atomic plane produces a spiral ramp about dislocations |
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| deformation of a metallic material by movement of dislocations through the crystal |
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| direction in the crystal in which the dislocation moves |
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| the plane swept out by the dislocation line during slip, normally the slip plane is a close packed plane if one exists in the crystal structure |
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| combination of a slip direction and slip plane |
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| small angle grain boundary |
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| surface or planar defect made up of an array of dislocations causing a small misorientation of the crystal across the surface of the imperfection |
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| a surface defect in an FCC materal caused by the improper stacking sequence of close-packed planes |
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| a point defect produced when an atom is removed from a regular lattice point and replaced with a different atom usually having a different size |
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| imperfections such as grain boundaries that form a 2D plane within the crystal |
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| small angle grain boundary composed of an array of edge dislocations |
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| a surface defect across which there is a mirror image misorientation of the crystal structure |
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| small angle grain boudnary made up of an array of screw dislocations |
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| point defect where an atom is missing from its regular cyrstallographic site |
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