Metallurgy Final Exam
metals - Answer metallic bonding, ductile, conductive
ceramics - Answer covalent/ionic bonding, brittle, insulator, stiff, high melting point
polymers - Answer covalent/Van der Waals bonding, weak, low temperatures, not stiff,
insulators
metallic bonds - Answer nondirectional, free electrons
covalent bonds - Answer directional, strong, no free electrons
ionic bonds - Answer two elements, strong, no free electrons, donating/accepting
electrons
FCC typical metals - Answer Al, Cu, Ni
BCC typical metals - Answer Fe, W
HCP typical metals - Answer Mg, Tl, Be
miller indices directions - Answer head minus tail, clear fractions, reduce to lowest
integers
miller indices planes - Answer find intercepts, take reciprocals, clear fractions, may have
to move origin
SC close-packed direction - Answer <100>
FCC close-packed direction - Answer <110>
BCC close-packed direction - Answer <111>
FCC close-packed planes - Answer (111)
HCP close-packed planes - Answer (0001) = basal
line defect/dislocation - Answer slipping allows ductility, blocking slip increases strength
strain hardening/cold working definition - Answer increasing number of dislocations
surface defects/grain boundaries/stacking faults - Answer small grains have more grain
boundaries with higher strength, N=2^(n-1) where "n" is ASTM grain size number, big
"n" means small size
, point defects - Answer substitutional, interstitial (smaller atoms), vacancies
solid solution strengthening definition - Answer substitutional or interstitial atoms
Diffusion - Answer movement of atoms through crystal structure
D=D_o^(-Q/(RT)) - Answer Q=activation energy, D=diffusion coefficient
more rapid diffusion happens when T ____ or Q ____ - Answer T increases, Q
decreases
Flux "J" - Answer how many atoms pass a given area per unit time
J=-D(c/x) - Answer (c/x) is concentration gradient
high flux causes _____ heat treatment - Answer quick
diffusion becomes important when T is - Answer T>=0.4T_m
tensile test gives (3 things on stress-strain graph) - Answer yield strength, tensile
strength, modulus of elasticity (stiffness)
yield strength - Answer when dislocations begin to move
tensile strength - Answer maximum load, necking occurs
modulus of elasticity (stiffness) - Answer slope of elastic (linear) region
% elongation - Answer (delta(L)/L_o)*100 =ductility
% area reduction - Answer (delta(A)/A_o)*100 =ductility
YS, TS, modulus ____ with high T - Answer decrease
% elongation and % area reduction ____ with high T - Answer increase
hardness test - Answer measure the penetration of surface by hard object, indicates
wear resistance
brinell hardness test - Answer sphere
rockwell hardness test - Answer diamond
impact test - Answer energy absorbed in sudden blow, high for FCC, want metal with
transition T below service temperature, Charpy test
metals - Answer metallic bonding, ductile, conductive
ceramics - Answer covalent/ionic bonding, brittle, insulator, stiff, high melting point
polymers - Answer covalent/Van der Waals bonding, weak, low temperatures, not stiff,
insulators
metallic bonds - Answer nondirectional, free electrons
covalent bonds - Answer directional, strong, no free electrons
ionic bonds - Answer two elements, strong, no free electrons, donating/accepting
electrons
FCC typical metals - Answer Al, Cu, Ni
BCC typical metals - Answer Fe, W
HCP typical metals - Answer Mg, Tl, Be
miller indices directions - Answer head minus tail, clear fractions, reduce to lowest
integers
miller indices planes - Answer find intercepts, take reciprocals, clear fractions, may have
to move origin
SC close-packed direction - Answer <100>
FCC close-packed direction - Answer <110>
BCC close-packed direction - Answer <111>
FCC close-packed planes - Answer (111)
HCP close-packed planes - Answer (0001) = basal
line defect/dislocation - Answer slipping allows ductility, blocking slip increases strength
strain hardening/cold working definition - Answer increasing number of dislocations
surface defects/grain boundaries/stacking faults - Answer small grains have more grain
boundaries with higher strength, N=2^(n-1) where "n" is ASTM grain size number, big
"n" means small size
, point defects - Answer substitutional, interstitial (smaller atoms), vacancies
solid solution strengthening definition - Answer substitutional or interstitial atoms
Diffusion - Answer movement of atoms through crystal structure
D=D_o^(-Q/(RT)) - Answer Q=activation energy, D=diffusion coefficient
more rapid diffusion happens when T ____ or Q ____ - Answer T increases, Q
decreases
Flux "J" - Answer how many atoms pass a given area per unit time
J=-D(c/x) - Answer (c/x) is concentration gradient
high flux causes _____ heat treatment - Answer quick
diffusion becomes important when T is - Answer T>=0.4T_m
tensile test gives (3 things on stress-strain graph) - Answer yield strength, tensile
strength, modulus of elasticity (stiffness)
yield strength - Answer when dislocations begin to move
tensile strength - Answer maximum load, necking occurs
modulus of elasticity (stiffness) - Answer slope of elastic (linear) region
% elongation - Answer (delta(L)/L_o)*100 =ductility
% area reduction - Answer (delta(A)/A_o)*100 =ductility
YS, TS, modulus ____ with high T - Answer decrease
% elongation and % area reduction ____ with high T - Answer increase
hardness test - Answer measure the penetration of surface by hard object, indicates
wear resistance
brinell hardness test - Answer sphere
rockwell hardness test - Answer diamond
impact test - Answer energy absorbed in sudden blow, high for FCC, want metal with
transition T below service temperature, Charpy test
