Deck 5: Engineering Materials

Question 1

Which one of the following properties do not apply to metals:

A)good thermal conductivity
B)high strength
C)high electrical resistivity
D)high stiffness

Answer 1

high electrical resistivity

Question 2

The predominant phase in the iron-carbon alloy system for a composition with 99% iron at room temperature is which one of the following:

A)austenite
B)cementite
C)delta
D)ferrite
E)gamma

Answer 2

ferrite

Question 3

As temperature is increased to slightly above 912 $\degree$ C (1674 $\degree$ F), pure iron transforms into which one of the following phases:

A)austenite
B)cementite
C)delta
D)ferrite

Answer 3

austenite

Question 4

The strength and hardness of steel increases as carbon content

A)increases
B)decreases

Question 5

Plain carbon steels are designated in the AISI code system by which one of the following:

A)01XX
B)10XX
C)11XX
D)12XX
E)30XX

Question 6

Which one of the following is not a common alloying ingredient in steel:

A)chromium
B)manganese
C)nickel
D)vanadium
E)zinc

Question 7

The principal strengthening mechanism in high-strength low-alloy (HSLA) steels is which one of the following:

A)alloying
B)heat treatment
C)high carbon content
D)precipitation hardening
E)work hardening

Question 8

Which of the following alloying elements are most commonly associated with stainless steel (two best answers):

A)chromium
B)manganese
C)molybdenum
D)nickel
E)tungsten

Question 9

High-speed steels are used in cutting tools for machining.Which of the following alloying elements are used in the highest proportion in high-speed steel (two best answers):

A)carbon
B)manganese
C)molybdenum
D)nickel
E)tungsten
F)Vanadium

Question 10

Which one of the following is the most important cast iron commercially:

A)ductile cast iron
B)gray cast iron
C)malleable iron
D)white cast iron

Question 11

From which of the following ores is aluminum derived:

A)alumina
B)bauxite
C)cementite
D)hematite
E)scheelite

Question 12

Which of the following metals is noted for its good electrical conductivity (one best answer):

A)copper
B)iron
C)nickel
D)tungsten

Question 13

Traditional brass is an alloy of which of the following metallic elements (two correct answers):

A)aluminum
B)copper
C)gold
D)tin
E)zinc

Question 14

Galvanized steel is steel that has been coated with which one of the following metals:

A)aluminum
B)chromium
C)nickel
D)tin
E)zinc

Question 15

Which one of the following metals is not one of the three metals used as the principal constituent in superalloys:

A)cobalt
B)chromium
C)iron
D)nickel

Question 16

A ceramic material can be defined as an organic compound consisting of a metal or semimetal and one or more nonmetals:

Question 17

Which of the following are properties generally associated with ceramic materials (three best answers):

A)chemical stability
B)electrically conductive
C)good ductility
D)high hardness
E)soluble in water
F)thermally insulating

Question 18

The difference between traditional ceramics and new ceramics is that most traditional ceramics are based primarily on silicates whereas the most new ceramics are based on oxides, carbides, or nitrides:

Question 19

Clays used in traditional ceramics are based primarily on which of the following (one best answer):

A)aluminum oxide
B)aluminum silicate
C)quartz
D)silicon carbide
E)silicon oxide

Question 20

Which of the following contains significant amounts of aluminum oxide (three correct answers):

A)alumina
B)bauxite
C)corundum
D)feldspar
E)kaolinite
F)quartz
G)sandstone
H)silica

Question 21

Which of the following ceramics are commonly used as abrasives in grinding wheels (two best answers):

A)aluminum oxide
B)calcium oxide
C)carbon monoxide
D)silicon carbide
E)silicon dioxide

Question 22

Which one of the following materials is closest to diamond in hardness:

A)aluminum oxide
B)carbon dioxide
C)cubic boron nitride
D)silicon dioxide
E)tungsten carbide

Question 23

Glass products are based primarily on which one of the following minerals:

A)alumina
B)corundum
C)feldspar
D)kaolinite
E)silica

Question 24

Glass ceramics are polycrystalline ceramic structures that have been transformed into a mostly glassy state:

Question 25

Which of the following best characterizes the structure of glass-ceramics:

A)95% polycrystalline
B)95% vitreous
C)50% polycrystalline

Question 26

Properties and characteristics of glass-ceramics include which of the following (two best answers):

A)efficiency in processing
B)electrical conductor
C)high thermal expansion
D)strong relative to other glasses

Question 27

Of the three polymer types, which one is the most important commercially:

A)elastomers
B)thermoplastics
C)thermosets

Question 28

Which one of the three polymer types is not a plastic:

A)elastomers
B)thermoplastics
C)thermosets

Question 29

Which one of the three polymer types does not involve cross-linking:

A)elastomers
B)thermoplastics
C)thermosets

Question 30

Which one of the three polymer types involves the greatest amount of cross-linking:

A)elastomers
B)thermoplastics
C)thermosets

Question 31

A branched molecular structure is stronger in the solid state and more viscous in the molten state than a linear structure for the same polymer:

Question 32

The defining property of a thermoplastic polymer is that it can be heated from a solid state to a viscous liquid state and then cooled back down to solid, and that this heating and cooling cycle can be applied multiple times without degrading the polymer:

Question 33

Which one of the following is the chemical formula for the repeating unit in polyethylene:

A)CH₂
B)C₂H₄
C)C₃H₆
D)C₅H₈
E)C₈H₈

Question 34

Which of the following plastics accounts for the highest volume of all plastics:

A)phenolics
B)polyethylene
C)polypropylene
D)polystyrene
E)polyvinylchloride

Question 35

Which of the following polymers are normally thermoplastic (three best answers):

A)acrylics
B)nylon
C)phenolics
D)polychloroprene
E)polyethylene
F)polyisoprene
G)Polyurethane

Question 36

Polystyrene is a linear polymer noted for its transparency and brittleness:

Question 37

Compared to thermoplastics, thermosetting polymers are characterized by which of the following properties (four best answers):

A)cannot be remelted
B)capable of higher service temperatures
C)higher modulus of elasticity
D)less ductile
E)lower modulus of elasticity
F)more ductile

Question 38

Curing (cross-linking) of thermosetting polymers is accomplished at the fabrication plants rather than the chemical plants that supply the starting materials:

Question 39

Curing of elastomers is known as which one of the following terms:

A)crystallization
B)firing
C)reinforcing
D)sintering
E)vulcanization

Question 40

The chemical formula for polyisoprene in natural rubber is which of the following:

A)CH₂
B)C₂H₄
C)C₃H₆
D)C₅H₈
E)C₈H₈

Question 41

The largest tonnage elastomer is which one of the following:

A)butyl rubber
B)isoprene rubber
C)polybutadiene
D)polyurethane
E)styrene butadiene rubber
F)thermoplastic elastomers

Question 42

A composite material is a material system composed of two or more physically distinct phases whose combination produces aggregate properties that are different from those of its constituents:

Question 43

The reinforcing phase is the matrix within which the secondary phase is imbedded:

Question 44

Which one of the following reinforcing geometries offers the greatest potential for improving strength and stiffness in the resulting composite material:

A)continuous fibers
B)discontinuous fibers
C)flakes
D)particles
E)infiltrated phase

Question 45

Which of the following materials are used as fibers in fiber-reinforced plastics (four best answers):

A)aluminum oxide
B)boron
C)cast iron
D)E-glass
E)epoxy
F)Kevlar 49
G)polyester
H)silicon

Question 46

Which of the following metals are widely used as the matrix metals in tungsten carbide and titanium carbide cermets (two best answers):

A)aluminum
B)chromium
C)cobalt
D)lead
E)nickel
F)Vanadium

Question 47

Which of the following metals are used as the matrix material in fiber-reinforced metal matrix composites (two best answers):

A)aluminum
B)copper
C)iron
D)magnesium
E)zinc

Question 48

Ceramic matrix composites are designed to overcome which of the following weaknesses of ceramics (two best answers):

A)compressive strength
B)hardness
C)hot hardness
D)modulus of elasticity
E)tensile strength
F)toughness

Question 49

Most plastic molding compounds include fillers and therefore can be classified as polymer matrix composites:

Question 50

Which one of the following polymer types are most commonly used in fiber-reinforced polymer matrix composites:

A)elastomers
B)thermoplastics
C)thermosets

Question 51

In the Boeing 787 Dreamliner, what percentage of the aircraft consists of composite materials (two correct answers):

A)12% by volume
B)20% by volume
C)50% by volume
D)80% by volume
E)12% by weight
F)20% by weight
G)50% by weight
H)80% by weight