Chapter 10-12 Flashcards
The first process that occurs in an annealing operation to restore a material’s properties to its pre-cold worked state is called: a)Grain growth
b)Recovery
c)Preheating
d)Recrystallization
b)Recovery
The number of primary slip systems in an HCP structure: a)3
b)6
c)12
d)24
a) 3
Which of the following materials can only be cold worked up to a maximum of approximately 40 %CW?a)Copper
b)Brass
c)1040 Steel
c)1040 Steel
Which phase of a 0.76 wt% C steel is stable above the eutectoid transformation line?
a)Austenite
b)Spherodite
c)Pearlite
d)Bainite
a)Austenite
Which statement about slip is NOT true?
a)The motion of dislocations in response to an externally applied shear stress is termed slip.
b)Operable slip systems depend on the residual stress of the material.
c)A slip system represents a slip plane – slip direction combination.
d)The slip system for an FCC structure is {111}, <110>.
b)Operable slip systems depend on the residual stress of the material.
Nucleation of proeutectoid ferrite at the austenite grain boundaries upon slow cooling of a hypoeutectoid steel occurs how?
a)Homogeneously
b)Heterogeneously
b)Heterogeneously
Which structure would require the shortest heat treatment time to form spheroidite?
a)Coarse pearlite
b)Lower bainite
c)Upper bainite
d)Fine pearlite
b)Lower bainite
Which thermal arrest line occurs between the austenite and ferrite + austenite phase fields?
a)A1
b)A3
c)A4
d)Acm
b)A3
The crystal structures of austenite and martensite, respectively are:
a)BCC and BCT
b)BCT and BCC
c)FCC and BCT
d)BCT and FCC
c)FCC and BCT
For a transformation to occur spontaneously, the change in free energy must be:
a)Positive
b)Neutral
c)Negative
c)Negative
The number of slip systems in an FCC structure:
a) 3
b) 6
c) 12
d) 24
c) 12
The recrystallization temperature is the temperature at which recrystallization just reaches completion in:
a) 1 s
b) 1 min
c) 1 hr
d) 1day
c) 1hr
Which of the following is the slip system for the BCC crystal structure?
a) {100} <110>
b) {110} <110>
c) {100} <010>
d) {110} <111>
d) {110} <111>
Which type of heat treatment requires the shortest amount of time?
a) Annealing
b) Normalizing
c) Austempering
d) Spheroidizing
b) Normalizing
Which of the following has no impact on the effectiveness of quenching of steel in water?
a) Salinity of the quenching medium
b) Temperature of the quenching medium
c) Velocity of the quenching medium
d) None of the above
d) None of the above
The ability of an alloy to be hardened by the formation of martensite as a result of a given heat treatment is called:
a) Quenching
b) Solution strengthening
c) Nucleation
d) Hardenability
d) Hardenability
Which structure would require the longest heat treatment time to form spheroidite?
a) Coarse pearlite
b) Lower bainite
c) Upper bainite
d) Fine pearlite
a) Coarse pearlite
Which structure is produced at the quenched end of a Jominy bar?
a) Ferrite
b) Pearlite
c) Cementite
d) Martensite
d) Martensite
The crystal structure of martensite is:
a) Complex orthorhombic
b) BCC
c) BCT
d) FCC
c) BCT
The driving force for the nucleation of a new phase is:
a) Latent heat of fusion
b) Undercooling
c) Nucleus shape function
d) Vin Diesel
b) Undercooling
The slip systems for BCC metals are {111} <110>
a) True
b) False
b) False
The ductility increases with increasing percent cold work.
a) true
b) false
b) false
In hot working, no strain hardening occurs
a) true
b) false
a) true
During grain growth, the grain boundary movement and atomic motion are in the same direction.
a) true
b) false
b) false
Ductile fracture is characterized by a flat fracture surface perpendicular to the tensile axis
a) true
b) false
b) false
Carbon atoms are located at the interstitial positions in iron-carbon alloys
a) true
b) false
a) true
The typical microstructure of hypereutectoid steels during very slow cooling consists of pearlite and proeutectoid cementite.
a) true
b) false
a) true
Two types of bainite are coarse and fine bainite
a) true
b) false
b) false
Critical quenching rate represents the minimum rate of quenching that will produce a fully martensite structure
a) true
b) false
a) true
The microstructure after full annealing is fine pearlite plus any proeutectoid phase
a) true
b) false
b) false
Which decreasing grain size, the strength of materials (1) and DBTT (ductile-to-brittle transition temperature) (2)
a) (1) decreases, (2) increases
b) (1) decreases, (2) decreases
c) (1) increases, (2) increases
d) (1) increases, (2) decreases
d) (1) increases, (2) decreases
Recrystallization temperature is the (1) temperature at which recrystallization just reaches completion in (2)
a) (1) minimum, (2) one hour.
b) (1) maximum, (2) one hour.
c) (1) minimum, (2) one minute.
d) (1) maximum, (2) one minute
a) (1) minimum, (2) one hour
Alloying elements have a strong influence on the eutectoid composition and temperature. Titanium (1) the eutectoid composition, and (2) the eutectoid temperature
a) (1) decreases, (2) increases
b) (1) decreases, (2) decreases
c) (1) increases, (2) increases
d) (1) increases, (2) decreases
a) (1) decreases, (2) increases
Bainite consists of
(a) martensite and spheroidite phases.
(b) spheroidite and austenite phases.
(c) austenite and ferrite phases.
d) ferrite and cementite phases
d) ferrite and cementite phases
Martensite has a non equilibrium (1) structure resulting from a diffusionless transformation of (2)
a) (1) single-phase, (2) austenite
b) (1) single-phase, (2) ferrite
c) (1) two-phase, (2) bainite
d) (1) two-phases, (2) cementite
a) (1) single-phase, (2) austenite
Two types of martensite are
a) upper and lower martensite
b) lath and lenticular martensite
c) coarse and fine martensite
d) hard and soft martensite
b) lath and lenticular martensite
Athermal transformation is (1) and (2) transformation
a) (1) time-dependent, (2) temperature-dependent
b) (1) time-dependent, (2) temperature-independent
c) (1) time-independent, (2) temperature-dependent
d) (1) time-independent, (2) temperature-independent
c) (1) time-independent, (2) temperature-dependent
Based on the hardness, the sequence of the follwoing four microstructure in plain carbin steels is
a) coarse pearlite < fine pearlite < martensite < tempered martensite
b) coarse pearlite < fine pearlite < tempered martensite < martensite
c) fine pearlite < coarse pearlite < martensite < tempered martensite
d) fine pearlite < coarse pearlite < tempered martensite < martensite
d) fine pearlite < coarse pearlite < tempered martensite < martensite
One Jominy distance is
a) 1/16 inch
b) 1/8 inch
c) 1/4 inch
d) 1/2 inch
a) 1/16 inch
