MSE 2100 multiple choice exams 1&2
The maximum stress on engineering stress-strain curve is called
(Ultimate) tensile strength (UTS)
What is the title of the textbook used in this class?`
Materials Science and Engineering, An Introduction
Young's modulus is defined as which of the following?
Ratio of stress over strain
What is the crystal structure for a material with the AX structure and the coordination number of 6?
Rock salt
Which of the materials below has the highest electrical conductivity?
Silver
When an engineer changes the microstructurer of an alloy to increase the difficulty of dislocation motion, which of the following will happen?
The metal will be strengthened
Which of the following is true about the size of Na+ and Na atom?
The radius of Na+ is smaller than the radius of Na atom
What of the following will happen as %CW in metallic alloy is increase?
Yield strength increases and ductility decreases
Determine the number of cations and anions in the unit cell of Rock-Salt structure
cations: 4 anions: 4
Which type of bonding has both of the following defining features: small difference in electronegativity and shared electrons?
covalent bonding
If you load a tensile specimen past its yield stress and then remove the force, the recovered strain is due to what type of deformation?
elastic
T/F: All ceramics contain only pure ionic bond
false
T/F: Fick's first law is only used to describe steady state diffusion
false
T/F: the Brinell hardness (HB) and Vickers hardness (HV) are always the same value for a given material
false
For a particular crystal structure, the slip direction is the direction in the slip plane having the
highest linear density
As temperature increases, how would the diffusion coefficient D change?
increase
As temperature increases, the fraction of the total number of atoms that are capable of diffusive motion will
increase
As temperature increases, the vacancy concentration in metallic crystal structure will
increase
As the impurity concentration of a metal is increased, how would the tensile and yield strengths change? (You may assume that the system stays a solid solution during the increase in the impurity concentration)
increase
As the degree of polymerization increases, the polymer molecular weight does which of the following?
increases
How does the increase in molecular weight influence a tensile modulus of a semi-crystalline?
no direct influence
The direction of an edge dislocation line is ______________ to the direction of Burgers vector, and _____________ to the direction of its motion under an applied shear stress
perpendicular perpendicular
Which of the following subshell(s) does the M shell contain?
s p d
For linear polymers, what type of bonding occure between adjacent linear chains?
secondary bonding
the linear polypropylene molecule segment shown is
syndiotactic (alternating)
Which cystal system(s) has the relationship a=b=y=90 and a=b=/c?
tetragonal
T/F: In an atom, the number of electrons and protons are equal
true
T/F: diffusion is the net movement of substance from a region of high concentration to a region of low concentration
true
T/F: the magnitude of the diffusion coefficient is indicative of the rate of atom motion and depends on nboth host and diffusing species as well as on temperature
true
T/F: the resistivity is an intrinsic property of a given material, and independent of sample size and geometry
true
T/F: two mechanisms for diffusion are possible: substitutional (or vacancy) and interstitial:
true
Which of the following is correct regarding the textbook used in this class?
-9th edition -Published by Wiley -One of the authors' last name is Callister
When the metal is annealed after cold working, which of the following occur?
-Ductility is increased -Strength of material is decreased -Elastic modulus of material stays the same -Grain size of material is increased
Which of the following show correct description about hardness?
-Hardness is a type of material's mechanical properties -Hardness relates to the resistance to plastic deformation -For a hardness test, the smaller indent means the larger hardness -There are several types of hardness test, such as Brinell, Vickers, Rockwell, etc.
What are the two factors influencing the ceramic crystal structure?
-charge neutrality -ratio of cation radius to anion radius
Which of the following would result in an increase of strength for most metals?
-decrease grain size -increase solute concentration -decrese in spacing between precipitates -increase in the number of dislocations (e.g. by cold working)
which of the following are line defects (1-D)?
-edge dislocatoin -screww dislocation
which of the following processes are included in the addition polymerization?
-initiation -propagation -termination
In addition polymerization, an initiator is used to break what type of bonds?
-primary -covalent -unsaturated
which of the following stages does the annealing contain?
-recovery -recrystallization -grain growth
which of thte following are point defects (0-D)?
-vacancy -interstitial atom -frenkel defect -schottky defect
what is the Atomic Packing Factor (APF) for FCC structure
0.74
Which of the following iron-carbon alloys would you expect to have a highest hardness:
0.95 wt% C
How many slip systems are there in FCC crystal structure?
12
There are 7 crystal system, which contains (how many) _________ Bravais lattices
14
what is the maximum number of electrons that M shell can contain?
18
The element Sulfur (S) has an atomic number of 16, what is the electronic structure
1s^2 2s^2 2p^6 3s^2 3p^4
What is the coordination number (number of nearest atoms) for atoms in the simple cubic unit cell?
6
Poisson's ratio for the majority of materials lies within which of the follwoing range?
From 0.25 to 0.5
which of the following is area defect (2-D)?
Grain boundary
Fick's first law equation
J=-D (dC/dx)
Which one of the following statements is true? (Cu has higher conductivity than Ni)
Adding Ni to Cu decreases its conductivity
