Exam 2 Flashcards
Which of the materials below has the lowest electrical resistivity?
polypropylene, copper, titanium dioxide, silicon
copper
A pair of cation vacancy-anion vacancy is called:
Schottky defect
Which of the following is a 2D defect?
Frenkel defect, Schottky defect, edge dislocation, screw dislocation, grain boundary
grain boundary
Which one of the following statements is true?
adding Ni to Cu increases its resistivity
adding Ni to Cu decreases its resistivity
adding Ni to Cu does not affect its resistivity
adding Ni to Cu increases its resistivity
As temperature increases, the diffusion coefficient D:
increases
Which one of the following statements is true for the non steady-state diffusion:
both concentration and flux do not depend on time
concentration depends on time but flux does not
concentration does not depend on time but flux does
both concentration and flux depend on time
both concentration and flux depend on time
Which one of the following statements is true for the steady-state diffusion:
both concentration and flux do not depend on time
concentration depends on time but flux does not
concentration does not depend on time but flux does
both concentration and flux depend on time
both concentration and flux do not depend on time
C(o) in the solution of the Fick’s Second Law fo non steady-state condition is:
initial concentration inside a sample
initial concentration at the samples’ surface at time 0
final concentration at the sample’s surface
final concentration inside the sample
initial concentration inside a sample
Poisson’s ration is defined as:
ratio of a lateral strain over a tensile strain
ratio of a tensile strain over a lateral strain
ratio of a lateral strain over a tensile strain multiplied by -1
ratio of a tensile strain over a lateral strain multiplied by -1
ratio of a lateral strain over a tensile strain multiplied by -1
For a given material with a tensile strength is 480 MPa and a yield strength is 240 MPa. You need to use this material in a device with the factor of safety N=3. What would be the maximum working load allowed for this material? 160 MPa 240 MPa 80 MPa 480 MPa
80 MPa
As the impurity concentration in solid solution of a metal is increased, the tensile strength:
decreases
increases
remains unchanged
increases
As %CW in metallic alloy is increased
yield strength increases and ductility decreases
As %CW in metallic alloy is increased
yield strength increases and tensile strength increases
A metal having a crystal structure with many operable slip systems will be relatively:
ductile
brittle
ductile
What type of point defects do you know?
vacancies, interstitials, substitutional
How does the number of vacancies change with increasing temperature?
increases
Two metals, A and B; both metals have FCC crystal structures. Metal A has an atomic radius of 0.3 nm and metal B has an atomic radius of 0.12 nm. Can these two metals form a complete substitution solid solution ( 0 % -100 % concentration)?
no, the radius is > 15%
Two metals, A and B. Metal A has FCC and metal B has BCC crystal structure. Metal A has an atomic radius of 0.121 nm and metal B has an atomic radius of 0.122 nm. Can these two metals form a a complete substitution solid solution (0 % -100 % concentration)?
no, they have different crystal structures
T/F: Two metals with similar electronegativity values can form substitutional solution
true
Which of the materials below has the highest electrical conductivity:
silver
silicon
polystyrene
silver
Which of the materials below has the lowest electrical conductivity: iron silicon polyethylene aluminum oxide
polyethylene
If a concentration of impurities increases electrical resistivity of a metal:
increases