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126 Cards in this Set
- Front
- Back
A type of secondary bond in which a temporary dipole induces another dipole in an adjacent atom is referred to as a
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van der waals bond
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When the types of bonds between polymer chains are primary bonds the resulting polymer is said to be
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primary-results in cross-linking and the resulting polymer is referred to as a thermoset
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The parameter that defines the degree order in a system is
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long range order parameter
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Many equations of the form: reaction rate = Cexp(-Q/RT) are referred to as _____ equations.
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arrhenius
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A measure of the stiffness of a material is referred to as the
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elastic modulus or Youngs’ modulus
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when properties of a material are independent of direction, the material is said to be
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isotropic
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the number of nearest neighbors that surround an atom or ion is the
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coordination number
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The combined First and Second laws of thermodynamics written in terms of G(P,T)
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= -SdT +VdP
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Elements in the same ____ have the same number of electrons in their outer, or valence shell.
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columns
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a type of primary bond formed between two electropositive elements when their average number of valence electrons is less than or equal to 3 is referred to as
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metallic
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In a plot of bond force against bond distance, the equilibrium separation distance between an ionically bonded pair of atoms is located at
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zero force
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In compounds involving more than one element, a ____ bond is favored as the difference in the electronegativity of the elements forming the compound increases.
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ionic
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The 3-D primary bond structure in a polymer results in a _____ polymer
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thermoset
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The _____ derivative of force versus bond distance evaluated at the equilibrium spacing is proportional to the Young’s modulus of the material.
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first
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Solidification of a pure crystalline substance is an ______ process.
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exothermic
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As the melting temperature of an element increases, the coefficient of thermal expansion tends to ______
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decrease
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_______ polymers tend to be recyclable.
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thermoplastic
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When the polymer chains are saturated, the only type of bond between polymer chains that can form are ______ bonds.
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secondary
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As the radius ratio increases, the coordination number ______
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increases
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The asymmetry in the bond energy curve is related to the ______ of the material.
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thermal expansion
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When hard spheres are packed in arrangements to form a BCC (Body Centered Cubic) structure, atoms touch along the _____ family of directions.
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<1 1 1>
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The hard sphere, FCC (Face Centered Cubic) structure has the same packing density as what other close-packed structure?
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HCP
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A lattice together with its basis is referred to as the _____
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crystal structure
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Fluids that show some degree of long range order are called
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liquid crystals
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There may/may not be more than one atom at each lattice point?
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may
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Diffusion along a grain boundary has a ______ activation energy than does bulk diffusion.
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lower
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Diffusion of carbon in BCC form of iron is ______ than in the FCC form of iron.
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higher
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The hard sphere packing in the HCP structure is the same as in the hard sphere _____ structure.
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FCC
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There is(are) ____ atom(s) per lattice point in FCC nickel.
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one
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Cu dissolved in Ni is an example of a _______ solid solution
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substitutional
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The effective penetration distance of a diffusing species is proportional to ______.
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square root of Dt
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Small cation and anion vacancy clusters that are formed in ionic solids are referred to as _______ defect.
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schottky
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The time dependent change in composition is related to the ________ (look at Fick’s Second law) of the composition versus distance relationship.
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curvature
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The movement of atoms in a pure material is termed ________.
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self-diffusion
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Fick’s second law defines diffusion that is time ______.
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dependent
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The activation energy for bulk diffusion is ______ than the activation energy for grain boundary diffusion.
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higher
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Decreasing temperature _______ the concentration of vacancies.
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decreases
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Diffusion along a dislocation has _____ activation energy than bulk diffusion.
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lower
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Because it is a thermally activated process, diffusivity ______ as temperature increases.
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increases
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Frenkel defects involving anions are ______ common than those involving cations.
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less
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As temperature decreases, bulk diffusion becomes _____ important than grain boundary diffusion.
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less
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Increasing the dislocation density by plastic deformation _______ the strength of an alloy.
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increases
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Diffusion of C in BCC iron is _____ than in FCC iron.
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faster
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Substitutional diffusion has ______ activation energy than interstitial diffusion.
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higher
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The energy of a dislocation is proportional to ____________.
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the square of the Burges vector, b2
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The motion of an edge dislocation that occurs when vacancies migrate to the extra half plane of atoms is referred to as ______.
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climb
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A two-dimensional defect composed of a regular array of edge dislocations is referred to as a(n) _________.
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tilt boundary
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The increase in the flow stress resulting from plastic deformation is usually called ________.
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dislocation hardening
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The Burgers vector of a _____ dislocation is parallel to the dislocation line.
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screw
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Increasing the grain size _______ the strength of a metal or alloy.
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decreases
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When rsolute < rsolvent the tendency is for the solute to segregate to the ______ side of the dislocation.
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compression
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Increasing the dislocation density ______ the strength of a metal or alloy.
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increases
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Because it is a thermally activated process, the probability of dislocation climb _______ as temperature increases.
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increases
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Actual critical resolved shear stresses are much ____ than theoretical strengths for metal crystals.
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lower
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In a symmetric tilt boundary, increasing the number of edge dislocations forming the boundary _______ the misorientation of the boundary.
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increases
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In an FCC material, slip tends to occur along _____ directions.
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<1 1 0>
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Dislocations are or are not thermodynamic defects?
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are not
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A _____ is a thermodynamic defect.
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vacancy
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Increasing the number of dislocations in a tilt boundary ______ the misorientation across the boundary.
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increases
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When R groups are randomly aligned on either side of a polymer chain the configuration is ______.
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atactic
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In amorphous materials below the __________, large-scale, molecular motion is not present and the material has a brittle liquid structure
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glass transition temperature, Tg
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________ is the arrangement of the rotatable bonds within a molecule.
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Conformation
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The ratio of the weight average molecular weight to the number average molecular weight is referred to as the _________.
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polydispersity
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The number of repeat units in a polymer is the _________________.
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degree of polymerization
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Decreasing the temperature of a glass forming system ________ the viscosity of the liquid.
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increases
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Below the glass transition temperature the entropy of the glass is ________ than the entropy of the corresponding crystalline form of the material.
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greater
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Increasing the number of side branches along a polymer backbone _______ its ability to crystallize.
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decreases
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Network modifiers are ________ of forming an extended primary bond network.
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incapable
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Increasing the degree of crystallinity of a polymer ___________ the modulus at a temperature above the glass transition temperature but below the melting temperature.
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increases
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Increasing the extent of change branching tends to _________ the ratio Tg/Tm.
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increase
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Increasing the extent of chain branching results in a(n) ____________ of the density of a polymer.
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decrease
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Changing the tacticity of a polymer does/does not affect the degree of crystallinity.
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does
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The maximum solid solubility on a phase diagram is controlled by factors described by _________.
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Hume-Rothery
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The proeutectoid phase for a hypoeutectoid alloy (for an Fe-C alloy) is _______.
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ferrite
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The melting reaction that occurs in an alloy system in which there is no change in composition when the solid transforms to the liquid is referred to as _____________.
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congruent melting
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The rule that relates the number of degrees of freedom to the number of components, phases, and state variables is the ______ phase rule.
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Gibbs
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The phase boundary separating a single-phase liquid region from a two-phase liquid plus solid region is referred to as the ________.
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liquidus
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When a liquid of one composition transforms to a liquid of another composition and a solid the reaction is said to be _______________.
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incongruent melting
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The phase boundary separating a solid region from a two-phase solid region is the _________.
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solvus
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On cooling, a liquid transforming to a liquid of a different composition and a solid is referred to as a __________ reaction.
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monotectic
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Compositions to the left of a eutectic are referred to as ___________.
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hypoeutectic
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A region that is chemically and structurally homogeneous is called a _________.
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phase
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When a solid melts congruently, the liquid and solid have ____________ composition(s).
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the same
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At constant temperature the fraction of the phases in a two-phase field _______ when the over all composition of the alloy is changed, but remains in the two-phase field.
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changes
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The maximum number of phases that can be in equilibrium in a three component system at one atmosphere is ______.
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four
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On cooling when a two-phase liquid plus solid transforms to a solid phase the transformation is _________ in nature.
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peritectic
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On cooling the peritectoid reaction written symbolically has ______________________.
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two phases going into one
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Steels whose compositions are to the left of the eutectoid are referred to as ___________ alloys.
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hypoeutectiod
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A _______________ is a newly formed phase, which can reduce its Gibbs free energy by either growing or dissolving.
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critical nucleus
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Two phases with same crystal structure and atomic spacings meet at a _________ interface.
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coherent
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The Body Centered Cubic (BCC) phase of iron is called ________.
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ferrite
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A steel microstructure consisting of spherical carbides distributed in ferrite is called ________.
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bainite
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When dislocations are present at an interface to relieve strain the interface is said to be a _____________________.
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semicoherent interface
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When nucleation occurs at random sites in the parent phase, the nucleation process is said to be ____________________.
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homogeneous nucleation
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The process by which powders are densified at elevated temperature to form nearly fully dense microstructure is ___________.
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sintering
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A two phase microstructure with alternate lamellar microstructure in steels is referred to as __________.
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pearlite
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The only phase which can produce martensite as a result of a rapid quench is _________.
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austenite
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Nucleation occurring at specific locations is referred to as ____________________.
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heterogeneous nucleation
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Increasing the interfacial free energy _________ the likelihood of homogeneous nucleation.
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decreases
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Decreasing the amount of undercooling below the eutectoid temperature __________ the pearlite spacing.
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increases
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The solubility of carbon at a particular temperature in iron is controlled by __________________.
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the size of the interstitial holes
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Iron carbide (Fe3C) is _________ with respect to graphite.
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metastable
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The _________ process occurs at temperature roughly equal to about 0.5 Tm resulting in a gradual decrease in strength with time.
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recovery
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Coring in metal castings is a direct consequence of _____________ cooling from the melt to room temperature.
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non-equilibrium
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Alloys that can form an extensive amount of _________ are materials that have high hardenability.
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martensite
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The solubility of carbon in austenite is ______ than the solubility of carbon in ferrite.
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greater
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As the undercooling decreases, the barrier to the nucleation event __________.
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increases
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________ is stress computed on the load divided by the initial cross sectional area.
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Engineering stress
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The temperature at which a reduction in the impact energy to cause fracture occurs is the ____________________.
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ductile to brittle transition temperature
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_________ is the process in which a material elongates with time under an applied load.
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Creep
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The parameter that characterizes the stress and strain at a given location ahead of a crack is referred to as the ____________.
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KIc, stress intensity factor.
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Reduction in stress that occurs when a component is subjected to a constant value of strain is referred to as ________________.
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stress relaxation
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The phenomenon known as ________________ is the result of dislocation-dislocation interactions in metallic crystals.
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strain hardening
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On an engineering stress-strain curve, the onset of plastic instability occurs at the _____________________.
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ultimate tensile stress
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Several classes of materials including carbon steels exhibit limiting stress amplitude called an _____________________, below which failure does not occur regardless of the number of fatigue cycles.
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endurance limit
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The ability of a material to resist penetration is _________.
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hardness
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When the applied stress exceeds a critical value called the ___________, deformation becomes permanent.
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yield point
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The onset of necking is observed in a(n) _____________.
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engineering stress- strain curve
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The presence of ______________ can significantly reduce electrical conductivity of a metal.
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dislocations
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As the hardness of a material increases, the diameter of the hardness indentation ______________.
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decreases
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Creep deformation can occur by dislocation __________.
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climb
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The slope of a stress-strain curve in the elastic region is generally ___________ for a ceramic material than a metal.
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greater
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The fracture stress in compression is _________ than the fracture stress in tension for a brittle ceramic.
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larger
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As a rule of thumb, the endurance limit correlates with _______ strength.
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tensile
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The upper and lower yield point is observed in
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alloys containing interstitials
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The strain rate in ________ creep is constant.
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stage 2
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