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Details Title: MSE Final Note Cards Description: Materials Science Vocab Total Flash Cards: 91 Created: 04/26/2007 19:11:55	To study from this set of flash cards, or to create your own your own study flash cards, register HERE. If you are already a registered user, CLICK HERE.
Cards Term Metallic Materials Definition Inorganic materials that are characterized by high thermal and electrical conductivities. Term ceramic materials Definition Materials consisting of metals and nonmetals. Term polymeric materials Definition Materials consisting of long molecular chains or networks of low weight elements such as carbon, hydrogen, oxygen and nitrogen. Term composite materials Definition Materials that are mixtures of two or more materials. Term electronic materials Definition Materials used in electronics. Term Anion Definition An ion with a negative charge Term cation Definition An ion with a positive charge. Term ionic bond Definition A primary bond resulting from the electrostatic attraction of oppositely charged ions. Term covalent bond Definition A primary bond resulting from the sharing of electrons. Term metallic bond Definition A primary bond resulting from the sharing of delocalized electrons in the form of an electron charge cloud by an aggregate of metal atoms. Term valence electrons Definition Electrons in the outermost shell that are most often involved in bonding. Term Crystal Definition A solid composed of atoms, ions or molecules arranged in a pattern that is repeated in three dimensions. Term unit cell Definition A convenient repeating unit of a space lattice Term body centered cubic Definition A unit cell with an atomic packing arrangement in which one atom is in contact with eight identical atoms located at the corners of an imaginary cube. Term face centered cubic Definition A unit cell with an atomic packing arrangement in which 12 atoms surround a central identical atom. PATTERN: ABCABC Term hexagonal close packed Definition A unit cell with an atomic packing arrangement in which 12 atoms surround a central identical atom. PATTERN: ABABAB Term atomic packing factor Definition The volume of atoms in a selected unit cell divided by the volume of the unit cell. Term Grain Definition A single crystal in a polycrystalline aggregate. Term Equiaxed Grains Definition Grains that are approximately equal in all directions and have random crystallographic orientations. Term Polycrystalline Definition A crystalline structure that contains many grains Term Solid Solution Definition An alloy of two or more metals or a metal and a nonmetal this is a single-phase atomic mixture. Term Alloy Definition A mixture of two or more metals or a metal and a nonmetal. Term Dislocation Definition A crystalline imperfection in which a lattice distortion is centered around a line. Term Grain Boundary Definition A surface imperfection that separates crystals (grains) of different orientations in a polycrystalline aggregate. Term Cold Working Definition Permanent deformation of metals and alloys below the temperature at which a strain free microstructure is produced continuously. Causes metal to be strain hardened. Term Hardness Definition A measure of the resistance of a material to permanent deformation. Term Slip Definition The process of atoms moving over each other during the permanent deformation of a metal. Term Slipbands Definition Line markings on the surface of a metal due to slip caused by permanent deformation. Term Slip System Definition A combination of a slip plane and a slip direction. Term Recovery Definition The first stage of the annealing process that results in the removal of residual stresses. Term Recrystallization Definition The second stage of the annealing process in which new grains start to grow. Term Twin (page 288) Definition A mirror image misorientation of the crystal structure which is considered a surface defect. Term electric current Definition The time rate passage of a charge through material. The number of coulumbs per second that passes a point in a material. Term electric current density Definition the electric current per unit area. Term electrical resistance Definition The measure of the difficulty of electric current’s passage through a volume of material. Term electrical resistivity Definition A measure of the difficulty of electric current’s passage through a unit volume of material. Term electrical conductivity Definition A measure of the ease with which electric current passes through a unit volume of a material. Term electrical conductors Definition A material with a high electrical conductivity. Term electrical insulators Definition A material with a low electrical conductivity. Term semiconductors Definition A material whose electrical conductivity is approximately midway between the values for good conductors and insulators. Term valence band Definition The energy band containing the valence electrons. Term conduction band Definition The unfilled energy levels into which electrons can be excited to become conductive electrons. Term intrinsic semiconductors Definition A semiconducting material that is essentially pure and for which the energy gap is small enough to be surmounted by thermal excitation; current carriers are electrons in the conduction band and holes in the valence band. Term electrons Definition A negative charge carrier. Term holes Definition A positive charge carrier. Term extrinsic semiconductors Definition A semiconductor whose conduction behavior is brought about by the introduction of extra electrons or positive holes by dopant species. Term donor level Definition In the band theory, local energy levels near the conduction band. Term acceptor level Definition In the band theory, local energy levels close to the valence band. Term engineering stresss Definition Average uniaxial force divided by original cross sectional area. Term engineering strain Definition change in length of a sample divided by original length of sample Term modulus of elasticity Definition stress divided by strain Term yield stress Definition The stress at which a specific amount of strain occurs in the engineering tensile test. Term ultimate tensile stress Definition The maximum stress in the engineering stress-strain diagram. Term ductile fracture Definition A mode of fracture characterized by slow crack propagation. Term brittle fracture Definition A mode of fracture characterized by rapid crack propogation. Term toughness Definition The resistance to fracture when a material is stressed. Term fracture toughness Definition The critical value of the stress-intensity factor that causes failure. Term necking Definition decreasing in cross sectional area Term ductile brittle transition temperature Definition Observed reduced ductility and fracture resistance of a material when temperature is low. Term elastic deformation Definition If a metal deformed by a force returns to its original dimensions after the force is removed. Term plastic deformation Definition When a metal is deformed to such an extent that is cannot fully recover. Term specific tensile stress Definition The tensile stress of a material divided by its density Term specific tensile modulus Definition The tensile modulus of a material divided by its density. Term isostress Definition The composite stress produces an equal stree condition on all layers Term isostrain Definition The stress causes uniform strain on all the composite layers. Term Equilibrium Definition When no macroscopic changes take place in a system. Term phase Definition A physically homogenous and distinct portion of a material system. Term liquidus Definition The temperature at which a liquid starts to solidify under equilibrium conditions. Term solidus Definition The temperature during the solidification of an alloy at which the last of the liquid phase solidifies. Term eutectic reaction Definition a phase transformation in which all liquid phase transforms on cooling into two solid phases isothermally. Term eutectic temperature Definition The temperature at which a eutectic reaction takes place. Term eutectic composition Definition The composition of the liquid phase that reacts to form two new solid phases at eutectic temperature. Term eutectic point Definition The point determined by the eutectic composition and temperature. Term invariant Definition equilibrium phase transformations involving zero degrees of freedom. Term hypoeutectic Definition one that is to the left of the eutectic point. Term hypereutectic Definition one that is to the right of the eutectic point. Term Austenite Definition An interstitial solid solution of carbon in FCC iron. Max solubility of carbon into it is 2.0 percent. Term ferrite Definition an interstitial solid solution of carbon in BCC iron. Max solubility of carbon in it is .02percent. Term cementite Definition The intermetallic compound Fe3C. A hard and brittle substance. Term pearlite Definition A mixture of ferrite and cementite phases in parallel plates produced by the eutectoid decomposition of austentite. Term Eutectoid Definition A steel with 0.8 percent carbon Term hardenability Definition The ease of forming martensite in a steel upon quenching from the austentite condition. Term martensite Definition A supersaturated interstitial solid solution of carbon in a body centered tetragonal iron. Term bainite Definition a nonlamellar eutectoid decomposition product of austentite. Term Jominy test Definition A bar is austentized and then quenched at one end. A test for hardenability. Term Materials Definition Substances at which something is composed or made. Term Materials Science Definition A discipline that is primarily concerned with the search for basic knowledge about the internal structure, properties and processing of materials. Term Materials Engineering Definition A discipline that is primarily concerned with the use of fundamental and applied knowledge of materials so that they can be converted into products needed by society. Term Metallic materials Definition Inorganic materials that are characterized by high thermal and electrical conductivities. Term Ferrous metals and alloys Definition Metals and alloys that contain a large percentage of iron. Term Nonferrous metals and alloys Definition Metals and alloys that do not contain iron.