1
A creep resistant material should have
Choose one answer.
a. a high elastic modulus.
b. a high melting temperature.
c. a high yield strength.
d. a long fatigue life.
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Question 2
A material has a melting point of 200 degrees Celsius, and we apply constant force loads at 20 degrees Celsius.
Choose one answer.
a. We do not expect creep deformation to occur.
b. Fast fracture should occur before creep deformation begins.
c. We do expect creep deformation to occur.
d. We do not have enough information to predict creep deformation.
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Question 3
A "critical crack length" is associated with
Choose one answer.
a. plastic yielding
b. creep permanent strain.
c. fast fracture.
d. non-protective oxide films.
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Question 4
A "ductile" material has a relatively high value of
Choose one answer.
a. percent elongation.
b. hardness.
c. elastic modulus.
d. ultimate tensile strength.
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Question 5
A "stiff" material has a relatively high value of
Choose one answer.
a. elastic modulus.
b. Poisson's ratio.
c. yield stress.
d. tensile strength.
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Question 6
A "strong" material has a relatively high value of
Choose one answer.
a. shear modulus.
b. yield stress.
c. percent elongation.
d. creep rate.
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Question 7
Charpy and Izod are names associated with equipment used to measure
Choose one answer.
a. hardness.
b. yield strength.
c. creep resistance.
d. toughness.
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Question 8
Creep deformation failure is a concern
Choose one answer.
a. in jet engines.
b. in automobile engines.
c. with aircraft wings.
d. with plastics at low temperatures.
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Question 9
Creep deformation is particularly a concern
Choose one answer.
a. at low temperatures.
b. at high temperatures.
c. when vibration is present.
d. when materials are in an oxygen-rich environment.
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Question 10
Failure by nucleation of surface cracks is particularly common with
Choose one answer.
a. impact testing.
b. fatigue testing.
c. creep testing.
d. tensile testing.
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Question 11
Fast fracture
Choose one answer.
a. is crack propagation at the speed of sound.
b. is always preceded by plastic yielding.
c. occurs only at low temperatures.
d. is observed in ceramics, but never in metals.
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Question 12
For ductile metals that strain harden, the tensile strength
Choose one answer.
a. may be either less than or greater than the yield stress.
b. is always less than the yield stress.
c. is always greater than the yield stress.
d. is not usually measured in the tensile test.
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Question 13
For most solids (metals, ceramics, rigid plastics) elastic deformation
Choose one answer.
a. is linear stress-strain behavior.
b. is parabolic stress-strain behavior.
c. obeys the Arrhenius law.
d. results in permanent shape change.
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Question 14
Hardness measurements
Choose one answer.
a. can identify polymers.
b. are completely non-destructive.
c. cannot be made on ceramics.
d. often follow heat treatment of metals.
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Question 15
Hardness measurements are useful because the resulting hardness number can be correlated with the material property of
Choose one answer.
a. yield stress.
b. creep rate.
c. fatigue life.
d. stiffness.
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Question 16
Linear oxidation rates are associated with
Choose one answer.
a. brittle fracture.
b. protective oxide films.
c. non-protective oxide films.
d. stainless steels.
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Question 17
Materials described as "ductile"
Choose one answer.
a. have low melting points.
b. have a high percent elongation.
c. have a low yield stress.
d. have low percent area reduction values.
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Question 18
Oxidation of metals
Choose one answer.
a. is always corrosive.
b. can sometimes be beneficial.
c. doesn't occur with many metals.
d. can be avoided by operating at high temperatures.
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Question 19
Plastic deformation
Choose one answer.
a. only occurs at elevated temperatures.
b. is irreversible shape change.
c. can sometimes be reversible shape change.
d. always fractures the part.
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Question 20
Preexisting micro cracks such as those found in sintered materials and large welded structures tend to promote failure by
Choose one answer.
a. fast fracture.
b. plastic yielding.
c. excessive creep strain.
d. non-protective oxide formation.
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Question 21
Rockwell and Brinell are names associated with equipment used to measure
Choose one answer.
a. stiffness.
b. hardness.
c. toughness.
d. fatigue life.
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Question 22
Some metals exhibit an "endurance limit" when loaded
Choose one answer.
a. in a tensile test.
b. in a fatigue test.
c. in a creep test.
d. in a hardness machine.
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Question 23
Sometimes we do not try to stop electrochemical attack, but allow it to proceed by
Choose one answer.
a. using materials with parabolic oxide growth rates.
b. utilizing a sacrificial cathode.
c. utilizing a sacrificial anode.
d. using materials with linear oxide growth rates.
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Question 24
The Arrhenius law is often found to describe
Choose one answer.
a. final hardness.
b. cycles to failure.
c. impact strength.
d. temperature variations.
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Question 25
The label of "hardening" is often used to describe the process of
Choose one answer.
a. annealing.
b. straining.
c. melting.
d. strengthening.
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Question 26
The sliding deformation of shear
Choose one answer.
a. always results in a decrease in volume.
b. occurs with constant volume.
c. always results in an increase in volume.
d. can either increase or decrease the volume.
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Question 27
The Standard Electrode Potential and Galvanic Series give information about
Choose one answer.
a. wet corrosion rates.
b. protective oxide films.
c. cathode and anode identification.
d. corrosion electrical currents.
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Question 28
The units of mechanical stress are
Choose one answer.
a. meters squared (or feet squared).
b. dimensionless.
c. newtons/meters squared (or pounds per square inch).
d. newtons (or pounds).
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Question 29
The units of Poisson's ratio are
Choose one answer.
a. pascals.
b. seconds.
c. meters squared.
d. dimensionless.
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Question 30
The units of the stress intensity factor are
Choose one answer.
a. pascals.
b. pascals times square root of meters.
c. percent per square meter.
d. dimensionless.
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Question 31
The units plotted on an S-N curve are
Choose one answer.
a. stress versus cycles.
b. stress versus strain.
c. strain versus time.
d. mass gain versus time.
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Question 32
To minimize the rate of wet corrosion we should
Choose one answer.
a. minimize the cathode area.
b. minimize the anode area.
c. make the anode and cathode areas as nearly equal as possible.
d. ignore areas as corrosion rate is not strongly dependent on area.
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Question 33
Which of the following promotes longer fatigue life?
Choose one answer.
a. Residual tensile stresses in the surface
b. Sharp corners in the sample geometry
c. Rough surface texture
d. Residual compression stresses in the surface
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Question 34
With surface treatments to a material, we can significantly
Choose one answer.
a. decrease creep strain rate.
b. increase stiffness.
c. increase impact energy absorption.
d. lengthen fatigue life.
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Question 35
"Brittle" materials exhibit
Choose one answer.
a. plastic deformation followed by elastic deformation.
b. elastic deformation followed by plastic deformation.
c. elastic deformation only.
d. plastic deformation only.
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Question 36
"Strain Hardening" refers to
Choose one answer.
a. necking down of polymer materials.
b. a property of brittle materials.
c. an increase in yield stress.
d. an increase in stiffness.
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Question 37
A disadvantage of aluminum alloys is that they
Choose one answer.
a. show creep deformation at relatively low temperatures.
b. oxidize rapidly.
c. cannot be alloyed to be heat treatable.
d. have low thermal conductivity.
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Question 38
A disadvantage of ceramics is they
Choose one answer.
a. often interact with atmospheres.
b. can be difficult to shape.
c. tend to deform by creep.
d. lose their ductility at low temperatures.
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Question 39
A disadvantage of titanium alloys is that
Choose one answer.
a. they are relatively expensive.
b. they are chemically reactive.
c. they have high strength to weight ratios.
d. they cannot be heat treated.
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Question 40
An advantage of ceramics is that
Choose one answer.
a. they are typically very hard.
b. they can easily be formed into complex shapes.
c. they have high percent elongation.
d. they have high densities.
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Question 41
An advantage of polymers is that
Choose one answer.
a. they usually have high melting temperatures.
b. they are hard and scratch resistant.
c. they have low elastic modulus values.
d. they are usually chemically inert.
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Question 42
At the glass transition temperature, thermoplastic polymers
Choose one answer.
a. show a volume change like melting ice.
b. change color.
c. change smoothly between rigid solid and viscous liquid.
d. permanently set up into rigid solids.
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Question 43
Cermets are composites of ceramic and metal. We would expect the resulting material to be
Choose one answer.
a. brittle and electrically insulating.
b. tough and hard.
c. flexible and high melting.
d. low density and soft.
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Question 44
Covalent bonds
Choose one answer.
a. result in ions packing close together.
b. are consistent with the high electrical conductivity of metals.
c. are easily broken during plastic deformation.
d. result in lower density solids.
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Question 45
Cross-linking a thermoplastic polymer
Choose one answer.
a. stiffens it.
b. causes it to flow more freely.
c. increases the glass transition temperature.
d. improves oxidation resistance.
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Question 46
During the "tempering" process of quench hardened steels
Choose one answer.
a. a hard, strong phase forms.
b. the steel softens slightly.
c. oxide formation is reduced.
d. the operating temperature of the final steel product is increased.
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Question 47
Engineering composites are often GRPR and CRPR, with the PR standing for
Choose one answer.
a. polycrystalline reinforced.
b. particle remelted.
c. polymer resins.
d. plastic remolded.
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Question 48
Low carbon or mild steels
Choose one answer.
a. are always quench hardened.
b. are the construction I-beam steels.
c. have particularly good corrosion resistance.
d. have relatively large amounts of other alloying elements.
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Question 49
Metals that exhibit high thermal conductivity generally
Choose one answer.
a. have low densities.
b. have high melting temperatures.
c. exhibit low electrical conductivity.
d. also exhibit high electrical conductivity.
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Question 50
Most often, engineering composites are chosen for
Choose one answer.
a. isotropic behavior (same in all directions).
b. light weight.
c. high melting temperature.
d. low cost.
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Question 51
Oxides, nitrides, and silicates predominate in
Choose one answer.
a. polymers.
b. ceramics.
c. composite materials.
d. metals.
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Question 52
Some polymers are rubbery because
Choose one answer.
a. covalent bonds readily stretch.
b. long chain molecules can uncoil and recoil.
c. polymer molecules easily slide over one another.
d. ionic bonds are easily broken.
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Question 53
The nature of metallic bonding accounts for
Choose one answer.
a. the light weight of some metals.
b. the high electrical and thermal conductivities of most metals.
c. the tendency of metals to corrode.
d. the brittleness of some metals.
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Question 54
The quench process in precipitation-hardened alloys
Choose one answer.
a. results in a hard structure.
b. results in a soft structure.
c. causes a phase change within the alloy.
d. is required to clean the alloy surface.
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Question 55
Thermoplastic polymers
Choose one answer.
a. are rubbery materials.
b. are permanent once cured.
c. are usable to higher temperatures than other polymers types.
d. can be repeatedly softened and stiffened.
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Question 56
Thermosetting polymers
Choose one answer.
a. are recyclable.
b. are frequently rubber-like.
c. include the hard, rigid Bakelite® and melamine plastics.
d. are usually clear or translucent.
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Question 57
To operate at the highest temperature, the materials class most often chosen is
Choose one answer.
a. composite materials.
b. metals.
c. polymers.
d. ceramics.
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Question 58
To resist shattering on sudden temperature change, it is desirable that glasses
Choose one answer.
a. have low thermal expansion coefficients.
b. have high thermal expansion coefficients.
c. have high softening temperatures.
d. have low densities.
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Question 59
Which of the following is not a composite material?
Choose one answer.
a. Nickel-based super alloy turbine blade
b. Wood
c. Reinforced concrete
d. Graphite reinforced tennis racket frame.
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Question 60
"Porous" ceramics include
Choose one answer.
a. tungsten carbide tool inserts.
b. porcelain plates.
c. silicon carbide abrasives.
d. diamonds.
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Question 61
A material with a relatively low value of impact energy absorbed
Choose one answer.
a. is considered to be ductile.
b. is considered to be brittle.
c. is most likely low density.
d. is most likely of a low melting temperature.
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Question 62
A predictor of creep deformation is a material's
Choose one answer.
a. endurance limit.
b. hardness number.
c. melting or softening temperature in kelvin.
d. elastic stiffness.
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Question 63
As a ductile metal is plastically deformed at cooler temperatures
Choose one answer.
a. its elastic stiffness increases.
b. its melting temperature decreases.
c. its yield stress increases.
d. its volume increases.
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Question 64
Crack detection by x-rays or chemical techniques is particularly important if it is suspected that failure might occur by
Choose one answer.
a. creep.
b. plastic yielding.
c. fast fracture.
d. oxidation.
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Question 65
Creep deformation is particularly a concern
Choose one answer.
a. when corrosion is occurring.
b. at low temperatures.
c. at high temperatures.
d. when vibration is present.
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Question 66
For a metal that work hardens severely
Choose one answer.
a. the elastic modulus is very low.
b. the percent elongation is very high.
c. the tensile strength is much higher than the yield stress.
d. the tensile strength is much lower than the yield stress.
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Question 67
Generally we find maximum toughness to fast fracture with
Choose one answer.
a. metals.
b. plastics.
c. ceramics.
d. composite materials.
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Question 68
If a material is to bend before it breaks, a relevant material property is
Choose one answer.
a. rupture modulus.
b. elastic modulus.
c. hardness number.
d. percent elongation.
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Question 69
If elastic deformation is to be a minimum, then
Choose one answer.
a. we should select the material with the highest elastic modulus.
b. we should select the material with the highest melting temperature.
c. we cannot generalize without knowing the geometry of the part.
d. we should select the material with the highest yield strength.
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Question 70
If our part must be light weight, then lacking other design constraints, our choice would most likely be a
Choose one answer.
a. plastic.
b. metal.
c. ceramic.
d. composite material.
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Question 71
Many steels exhibit an "endurance limit" when tested in
Choose one answer.
a. creep.
b. impact.
c. fatigue.
d. tension.
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Question 72
The class of materials stable to the highest temperatures is
Choose one answer.
a. metals.
b. polymers.
c. composite materials.
d. ceramics.
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Question 73
The flexed rotating beam apparatus compares materials in
Choose one answer.
a. fatigue failure.
b. creep failure.
c. stress corrosion.
d. elastic recovery.
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Question 74
The stress-strain curve of an elastomer (rubber-like material) is usually
Choose one answer.
a. linear.
b. non-linear.
c. restricted to approximately 0.2% strain.
d. showing a higher elastic modulus than for most metals.
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Question 75
The units of specific gravity are
Choose one answer.
a. kg/m³.
b. kilograms.
c. m/s².
d. dimensionless.
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Question 76
To minimize creep rate, it is desirable to have metals
Choose one answer.
a. with fine (small) grains.
b. with coarse (large) grains.
c. with high yield strengths.
d. with low melting temperatures.
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Question 77
To predict fast fracture, materials are compared in terms of
Choose one answer.
a. critical stress intensity factor.
b. hardness number.
c. density.
d. melting temperature.
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Question 78
To slow electrochemical attack
Choose one answer.
a. the cathode areas should be small.
b. the anode areas should be small.
c. metals should be widely separated in the electrochemical series.
d. surfaces should be rough rather than smooth.
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Question 79
Which of the following in not a condition for electrochemical attack?
Choose one answer.
a. Non-protective oxide film
b. Contact with an aqueous solution
c. Electrical contact between anode and cathode
d. Two dissimilar metals
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Question 80
Which of the following is not a way to improve fatigue life?
Choose one answer.
a. Using polished surfaces
b. Strain hardening
c. Introducing compressive surface residual stresses
d. Reducing geometries of sharp corners
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Question 81
With electrochemical attack, the dissolving metal is
Choose one answer.
a. more dense metal.
b. the standard electrode.
c. the cathode.
d. the anode.
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Question 82
With fatigue failure, micro cracks grow until the part fails by
Choose one answer.
a. creep.
b. fast fracture.
c. excessive plastic deformation.
d. necking down to concentrate stress.
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Question 83
With galvanized sheet (zinc on steel)
Choose one answer.
a. the iron is the sacrificial anode.
b. the zinc is the sacrificial anode.
c. either iron or zinc can be the anode.
d. both the iron and zinc corrode simultaneously.
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Question 84
"Ductile" materials have
Choose one answer.
a. high percent elongation.
b. low yield strength.
c. low melting temperatures.
d. low density.
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Question 85
A disadvantage of mechanical forming is that
Choose one answer.
a. though stronger, final parts are also more brittle.
b. long rod and tube shapes cannot be formed.
c. it cannot be used with materials at high temperatures.
d. porous, low density products may result.
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Question 86
A disadvantage of sintering is that
Choose one answer.
a. parts are generally limited to be small in size.
b. porous, low-density products may result.
c. preferred textures may be in the final products.
d. only low-temperature materials can be formed this way.
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Question 87
A limitation of forming by casting is that
Choose one answer.
a. chemically reacting materials cannot be cast.
b. extensive post machining may be required.
c. some materials deteriorate before they melt.
d. porous, low-density products may result.
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Question 88
A process capable of forming an intricate geometrical shape is
Choose one answer.
a. directional solidification.
b. preferred orientation stamping.
c. oxyacetylene torch cutting.
d. lost wax casting.
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Question 89
An advantage of forming by casting is
Choose one answer.
a. the porous product can be utilized for specialized applications.
b. dissimilar materials can be joined together.
c. metals can be strengthened while being shaped.
d. intricate shapes can be formed in a single step.
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Question 90
An advantage of forming by mechanical deformation is
Choose one answer.
a. dissimilar materials can be joined together.
b. intricate shapes can be formed in a single step.
c. the porous product can be utilized for specialized applications.
d. metals can be strengthened while being shaped.
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Question 91
An advantage of forming by sintering is
Choose one answer.
a. refractory (very high melting) materials can be shaped.
b. metals can be strengthened while being shaped.
c. dissimilar materials can be joined together.
d. preferred texture can be imparted to the final part.
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Question 92
An advantage of MIG (metal-inert-gas) welding is
Choose one answer.
a. dissimilar materials can be joined together.
b. it can be used to cut as well as join metals.
c. acetylene gas is explosive.
d. it can be automated for use with industrial robots.
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Question 93
Caution must be used with sintering because
Choose one answer.
a. very fine powders can be explosive.
b. large electrical currents pass through the parts.
c. temperatures involved are higher than the melting temperatures.
d. corrosive chemicals are required.
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Question 94
Ceramics are most often shaped by
Choose one answer.
a. casting.
b. sintering.
c. compressive mechanical forming.
d. TIG welding.
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Question 95
Common "stick welding" is more formally known as
Choose one answer.
a. MIG welding.
b. TIG welding.
c. oxyacetylene welding.
d. shielded metal arc welding.
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Question 96
Dislocations in metals are
Choose one answer.
a. displaced grain boundaries.
b. linear geometric defects.
c. impurity concentrations.
d. responsible for elastic deformation.
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Question 97
The heat affected zone in welded stainless steels
Choose one answer.
a. refers to the weld filler metal.
b. is stronger than the surrounding metal.
c. is severely work hardened.
d. may no longer be corrosion resistant.
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Question 98
Thermosetting polymers are frequently shaped by
Choose one answer.
a. casting.
b. extrusion.
c. TIG welding.
d. hot rolling.
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Question 99
When a cold worked metal is annealed,
Choose one answer.
a. its yield stress increases.
b. its fracture toughness is decreased.
c. recrystallization grows new grains within the metal.
d. its dislocation density is increased.
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Question 100
Which statement does not apply to TIG welding?
Choose one answer.
a. It frequently is used to cut as well as join.
b. The tungsten electrode is not consumed during the welding.
c. TIG requires greater operator skill than other welding processes.
d. It is usually the first choice for joining stainless steels.
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