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| In metals at temperatures below half of the melting temperature, plastic strain is due to ___ motion. |
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| To increase the room-temperature yield strength of a metal containing dislocations, it is necessary to introduce ___ to dislocation motion. |
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| Strain-hardening results from ___ strain. |
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Definition
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| Edge dislocations whose tangent and Burger's vector are not on a most closely packed plane are ___. |
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| The increase in tensile and shear yield strength due to the strain hardening of metals is proportional to the dislocation density to the ___ power. |
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Definition
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| A(n) ___ source produces new dislocations when a segment of a dislocation is pinned at two ends on a slip plane and the resolved shear stress reaches a critical value. |
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| A recovery ___ is when a strain_hardened metal is heated to an elevated temperature and the ductility is increase, but no new grains form. |
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Definition
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| If a strain-hardened metal is heated to an elevated temperature and new grains form, this process is ___. |
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| If a crystal contains only two edge dislocations with Burger's vectors of opposite signs, and they come together on the same slip plane the resulting number of dislocations is equal to ___. |
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Definition
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| As a result of an anneal, the dislocation density is ___. |
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Definition
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| The yield strength of metals is proportional to the negative __ power of the grain diameter. |
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Definition
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| When edge dislocations on a close-packed plane in a grain cannot slip in an adjacent grain with differently oriented close-packed planes, dislocations form a(n) ___ at a grain boundary. |
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Definition
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| A steel with a small grain size has a ___ yield strength than the same steel with a larger grain size. |
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Definition
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| ___ strengthening is when small hard particles are added to a ductile metal. |
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Definition
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| In dispersion-strengthened metals, the strength and elastic modulus of the alloy are proportional to the ___ fraction of the dispersion. |
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Definition
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| One disadvantage of dispersion-strengthened metals at high temperatures is that the dispersion and the matrix are not in ___ with each other, and as a result the matrix and dispersion may react with each other. |
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Definition
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| Metal alloys dispersion strengthened with oxide particles are usually produced by ___ metallurgy techniques. |
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Definition
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| In solid-solution strengthened metals, substitutional and interstitial solid-solution atoms interact with ___ dislocations in the metal. |
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Definition
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| A large substitutional atom is attracted to the region of an edge dislocation that has ___ strains. |
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Definition
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Term
| The increase in strength due to solid-solution strengthening is proportional to the __ power of the atom fraction of solute atoms. |
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Definition
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| The concentration of solid-solution atoms at a stationary edge dislocation is greater than the average concentration of solid-solution atoms in the solid, and this results in the ___ yield point in low-carbon steels. |
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Definition
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Term
| Strengthening by cooling a solid solution and forming small particles of a new phase is called ___ hardening. |
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Definition
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| The increase in yield strength of a precipitation-hardened alloy is ___ proportional to the spacing between the particles. |
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Definition
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| The first step in the precipitation-hardening process is the ___ treatment to produce a uniform distribution of solute atoms in the grains. |
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Definition
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| The second step in the precipitation-hardening process is to ___ the alloy to maintain a uniform distribution of atoms in the grains at low temperature. |
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Definition
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| The third step in the precipitation-hardening process is to ___ or ___ the alloy to form the precipitate. |
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Definition
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| During precipitation-hardening, at peak strength the precipitate changes from coherent to ___. |
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Definition
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| ___ or ___ stresses result from strains that are not due to applied external forces. |
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Definition
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Term
| Whiskers have one ___ dislocation up the center of the whisker. |
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Definition
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| In brittle ceramics, the fracture strength is lower than the ___ strength. |
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Definition
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| Polycrystalline MgO is brittle at room temperature because to maintain continuity with plastic strain in a polycrystalline material, there must be at least ___ active slip systems. |
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Definition
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| In brittle materials, the easiest way to increase the ___ strength is to decrease the size of cracks and pores. |
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Definition
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| In partially stabilized zirconia (ZrO2), the addition of materials such as MgO or CaO lowers the temperature of the ___ transformation of the tetragonal to the monoclinic phase. |
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Definition
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Term
| To temper glass, the glass is initially heated to a temperature above the glass transition temperature but below the ___ temperature. |
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Definition
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| In tempered glass, the stress in outer surface is in a state of ___. |
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Definition
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| In ___ tempering of glass, ions larger than Si, such as K and Na, are introduced into the surface. |
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Definition
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Term
| One method of strengthening the ceramic Si3N4 is by producing a(n) ___ microstructure. |
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Definition
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| The theoretical and observed tensile yield strength of whiskers is approximately equal to ___ of the elastic modulus. |
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Definition
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| A carbon ___ is one or more sheets of graphite wrapped into a cylinder terminated at the ends. |
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Definition
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| A sheet of graphite that is one atom layer thick is called ___. |
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Definition
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| Side branches on a polymer ___ the density, crystallinity, yield strength, and elastic modulus. |
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Definition
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| An increase in crystallinity in a polymer ___ the yield strength. |
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Definition
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Term
| To orient the LCMs of a polymer, it must be rapidly deformed just above the ___ transition temperature and below the melting temperature. |
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Definition
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Term
| If two polymers mix in the liquid state, this is called a(n) ___. |
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Definition
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| A(n) ___ is a material added to a polymer to lower the glass transition temperature. |
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Definition
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Term
| The chlorine atoms on PVC polymer LCMs increase the amount of ___-dipole bonding between LCMs. |
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Definition
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Term
| The LCMs of PMMA cannot easily slide past each other at room temperature, because of ___ hindrance. |
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Definition
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Term
| PEEK, along with other polymers, such as PPE, PEK, PSU, and PES, is a high- performance ___ polymer. |
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Definition
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Term
| LCMs of ABS have mers of PAN, BR, and PS on one polymer chain, resulting in a(n) ___. |
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Definition
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| True or false: Thermoset polymers melt when heated to a high temperature in the presence of oxygen. |
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Definition
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| The epoxy resin LCMs are ___ with covalent chemical bonds after mixing with a hardener. |
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Definition
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| In a network thermoset polymer, there is _-dimensional covalent bonding. |
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Definition
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| ___ is the least expensive process for strengthening metals, because no expensive alloy elements are added, and it is only necessary to deform the metal with standard deformation processes. |
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Definition
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| Solid solution strengthening is ___ with designs that require the part to be heated during fabrication by processes such as welding or hot working. |
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Definition
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| If a precipitation hardened alloy that is aged to peak strength is heated during processing to produce the part, the strength may be ___. |
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Definition
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Term
| The requirement to use powder metallurgy techniques makes oxide dispersion strengthened metals ___ in comparison to other metal strengthening techniques. |
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Definition
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| In developing a precipitation hardened aluminum-copper alloy, what is the maximum amount of copper in weight percent that can be completely in solution in a solid aluminum-copper alloy at any temperature? |
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Definition
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| In selecting a unalloyed alumina material for a design, it would be expected that the one with the highest density would have the ___ tensile strength. |
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Definition
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| The use of polymer blends and alloys in a design ___ the ability to recycle the material. |
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Definition
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| True or False: Thermoset polymers can be melted for processing or recycling. |
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Definition
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| Strain-hardening in metals is due to... |
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Definition
| The creation of immobile dislocations by dislocation reactions |
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Term
| Which of the following strengthening processes in metals does not require the addition of foreign atoms or compounds to a pure metal? |
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Definition
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Term
| Which of the following is not expected to provide solid-solution strengthening? |
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Definition
| A small interstitial atom in the compressive strain region of an edge dislocation. |
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Term
| The peak strength in a precipitation-hardened alloy occurs when |
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Definition
| The precipitate changes from coherent to incoherent. |
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Term
| Which of the following aging treatments of a precipitation-hardened alloy would be expected to result in the most stable precipitate particles? |
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Definition
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Term
| Which of the following procedures would not increase the fracture strength of a polycrystalline ceramic? |
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Definition
| Solid-solution alloy additions to increase the yield strength |
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Term
| Which of the following procedures would not be expected to increase the yield strength of LDPE? |
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Definition
| Quenching the LDPE to room temperature from the liquid state |
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Term
| Which of the following materials is not cross-linked? |
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Definition
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Term
| Which of the following processes would you expect to produce small-diameter PE fibers that have a very high tensile strength? |
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Definition
| Draw fibers at a temperature just above the glass transition temperature |
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