MTE 271 FINAL EXAM QUESTIONS WITH VERIFIED SOLUTIONS LATEST UPDATE 2026
This material is generally an inorganic nonmetallic material, does not conduct heat well and must
be heated to very high temperatures before melting. Also this material is very strong and hard,
but also very brittle. - Answers ceramic
These materials have good electrical and thermal conductivities, relatively high strength, high
stiffness, ductility or formability, and shock resistance. These materials are particularly useful for
structural or load-bearing applications - Answers metals and alloys
These materials are typically organic materials, are typically good electrical and thermal
insulators, and generally have very good strength-to-weight ratios. They are generally not
suitable for high temperature applications. - Answers polymers
An engineer is designing a plane. There is a choice of aluminum or a composite material. The
composite weighs half that of aluminum. Choosing the composite will not affect fuel costs. - Answers
false
Density is a ratio of _______________. - Answers Weight/Volume
What is the atomic number of an atom? - Answers The atomic number of an atom is the number of
protons per atom
Most of the mass of the atom is contained within the ____________. - Answers nucleus
The Pauli Exclusion Principle states that within each atom, no two electrons can have the same
four _____________ numbers - Answers quantum
The valence of an atom is the number of electrons in an atom that do not participate in bonding
or in chemical reactions. - Answers false
Metallic, covalent, and ionic bonds are known as ________? - Answers primary bonds
Bonds that are formed by the sharing of valence electrons among two or more atoms are
___________? - Answers covalent bonds
In ionic bonds the atom that contributes an electron and has a positive charge as a result is called
the __________. The atom in iconic bonding that accepts an electron and has a negative charge
as a result is called the ___________. - Answers cation, anion
Materials with high binding energy also have __________ strength and __________ melting
temperature. - Answers high, high
A lattice is a collection of points named ____________, which are arranged in a periodic pattern
so the surroundings of each point in the lattice are identical. - Answers lattice points
Which of the following choices includes the names for all three cubic crystal Bravais lattices: -
Answers simple cubic, face-centered cubic, body-centered cubic
The _______________ is the number of atoms touching a particular atom, or the number of
nearest neighbors for that particular atom. - Answers coordination number
Materials that can have more than one crystal structure are called polymorphic or allotropic. The
term _________________ refers to pure elements with more than one crystal structure. The term
_________________ is used for compounds with more than one crystal structure - Answers
allotropic, polymorphic
In all crystal structures, there are small holes between the usual atoms into which smaller atoms
may be placed. These locations are called _________________ sites. - Answers interstitial
Covalently bonded materials frequently have complex structures in order to satisfy the
directional restraints imposed by the bonding. - Answers true
The ratio of sizes of the ionic radii of anions and cations in a cell has no influence on the manner
of packing of that cell. - Answers false
Crystal structures with ions must have/exhibit ____________. - Answers electrical neutrality
For the cubic crystal system, how many atoms are there in a single simple cubic (SC) unit cell?
In a face-centered cubic (FCC) unit cell? In a single body-centered cubic (BCC) unit cell? - Answers SC:
1, FCC: 4, BCC: 2
What is the mathematical relationship between the atomic radius (r) and the lattice parameter
(a0) in the BCC structure? - Answers sqrt(3)a0 = r
What is the relationship between a Miller index value and its negative value? - Answers The vectors
represent the same line, but point in opposite directions
The direction of a Miller indices and its multiple are the same. - Answers true
Planes and their negative values are identical because they are _________ - Answers the negative
plane also has the same planar density and pattern of atoms as the "positive" plane
, X-rays that strike certain crystallographic planes at specific angles are reinforced rather than
annihilated. This phenomenon is called ___________ - Answers diffraction
A Frenkel defect in an ionic crystal is composed of which of the following? - Answers - An anion
interstitial + an anion vacancy
- A cation interstitial + a cation vacancy
The solvent is an element or compound that is present in ________. - Answers the greatest amount
Decreasing the number of grains or increasing the grain size of a metallic material causes the strength
of the metal to decrease - Answers true
Small angle boundaries formed by edge dislocations are called tilt boundaries. Small angle boundaries
formed by screw dislocations are called twist boundaries. - Answers true
Stacking faults are defects that really interfere with the slip process. Which of the following
statements best describes a stacking fault - Answers A stacking fault represents an error in the
stacking sequence of close packed planes resulting in a small region that has HCP stacking rather than
FCC stacking
Dislocations represent one type of defect in a crystal. Dislocations are responsible for plastic
deformation. What are the two fundamental types of dislocations? - Answers edge and screw
The surface energy of a single crystal depends on the crystallographic orientation with respect to the
surface. - Answers true
Once a system is at a state of equilibrium, a shift from equilibrium may result if one alters which of
the following variables? - Answers - pressure
- composition
- temperature
A solidus line separates which of the following phase fields? - Answers α and L + α
A binary composition vs. temperature phase diagram for an isomorphous system will be composed of
regions that contain which of the following phases and/or combinations of phases? - Answers α,
liduid + α, and liquid
A eutectic reaction involves which of the following phases? - Answers One liquid phase and two solid
phases
"Coring," which represents a form of non-equilibrium solidification, results in variations in the
composition of a solidifying alloy. Coring occurs because of rapid solidification (i.e., the alloy solidifies
faster than
diffusion can occur to equilibrate composition). - Answers true
Name the two general activities that accompany a phase transformation - Answers growth and
nucleation
In precipitation hardening, the solution heat treatment consists of (1) heating the alloy to a
temperature such that all solute atoms are dissolved to form a single-phase solid solution, (2)
quenching to produce a non-equilibrium supersaturated solid solution, and aging at a lower
temperature to form a uniform distribution of small precipitates - Answers true
For most technologically important metal alloys, the usual state or microstructure is: - Answers a
metastable one
Can interstitial atoms ever exhibit unlimited solubility in a metal? - Answers no
Which of the following is not a criterion for unlimited solubility of an alloy? - Answers The atoms or
ions must have a 50% or higher difference in atomic radius size
Dislocations are defects that are responsible for plastic deformation in crystalline solids. Which
of the following correspond to the name of the process by which dislocations move in crystalline
solids? - Answers glide and slip
For a particular crystal structure, the slip direction is that direction in the slip plane having the
________ - Answers highest linear density
Which kind of fracture is associated with the intergranular crack propagation mechanism? - Answers
brittle
In which of the following phenomena do free electrons play a role: thermal conduction or
thermal expansion? - Answers thermal conduction
How do thermal conductivities of single crystals and polycrystalline materials compare? - Answers
Single crystal conductivity is greater.
The typical electrical conductivity value/range for materials are: - Answers Semiconductor 10⁻⁶ to 10⁴
(Ω-m)⁻¹
Metal 10⁷ (Ω-m)⁻¹
This material is generally an inorganic nonmetallic material, does not conduct heat well and must
be heated to very high temperatures before melting. Also this material is very strong and hard,
but also very brittle. - Answers ceramic
These materials have good electrical and thermal conductivities, relatively high strength, high
stiffness, ductility or formability, and shock resistance. These materials are particularly useful for
structural or load-bearing applications - Answers metals and alloys
These materials are typically organic materials, are typically good electrical and thermal
insulators, and generally have very good strength-to-weight ratios. They are generally not
suitable for high temperature applications. - Answers polymers
An engineer is designing a plane. There is a choice of aluminum or a composite material. The
composite weighs half that of aluminum. Choosing the composite will not affect fuel costs. - Answers
false
Density is a ratio of _______________. - Answers Weight/Volume
What is the atomic number of an atom? - Answers The atomic number of an atom is the number of
protons per atom
Most of the mass of the atom is contained within the ____________. - Answers nucleus
The Pauli Exclusion Principle states that within each atom, no two electrons can have the same
four _____________ numbers - Answers quantum
The valence of an atom is the number of electrons in an atom that do not participate in bonding
or in chemical reactions. - Answers false
Metallic, covalent, and ionic bonds are known as ________? - Answers primary bonds
Bonds that are formed by the sharing of valence electrons among two or more atoms are
___________? - Answers covalent bonds
In ionic bonds the atom that contributes an electron and has a positive charge as a result is called
the __________. The atom in iconic bonding that accepts an electron and has a negative charge
as a result is called the ___________. - Answers cation, anion
Materials with high binding energy also have __________ strength and __________ melting
temperature. - Answers high, high
A lattice is a collection of points named ____________, which are arranged in a periodic pattern
so the surroundings of each point in the lattice are identical. - Answers lattice points
Which of the following choices includes the names for all three cubic crystal Bravais lattices: -
Answers simple cubic, face-centered cubic, body-centered cubic
The _______________ is the number of atoms touching a particular atom, or the number of
nearest neighbors for that particular atom. - Answers coordination number
Materials that can have more than one crystal structure are called polymorphic or allotropic. The
term _________________ refers to pure elements with more than one crystal structure. The term
_________________ is used for compounds with more than one crystal structure - Answers
allotropic, polymorphic
In all crystal structures, there are small holes between the usual atoms into which smaller atoms
may be placed. These locations are called _________________ sites. - Answers interstitial
Covalently bonded materials frequently have complex structures in order to satisfy the
directional restraints imposed by the bonding. - Answers true
The ratio of sizes of the ionic radii of anions and cations in a cell has no influence on the manner
of packing of that cell. - Answers false
Crystal structures with ions must have/exhibit ____________. - Answers electrical neutrality
For the cubic crystal system, how many atoms are there in a single simple cubic (SC) unit cell?
In a face-centered cubic (FCC) unit cell? In a single body-centered cubic (BCC) unit cell? - Answers SC:
1, FCC: 4, BCC: 2
What is the mathematical relationship between the atomic radius (r) and the lattice parameter
(a0) in the BCC structure? - Answers sqrt(3)a0 = r
What is the relationship between a Miller index value and its negative value? - Answers The vectors
represent the same line, but point in opposite directions
The direction of a Miller indices and its multiple are the same. - Answers true
Planes and their negative values are identical because they are _________ - Answers the negative
plane also has the same planar density and pattern of atoms as the "positive" plane
, X-rays that strike certain crystallographic planes at specific angles are reinforced rather than
annihilated. This phenomenon is called ___________ - Answers diffraction
A Frenkel defect in an ionic crystal is composed of which of the following? - Answers - An anion
interstitial + an anion vacancy
- A cation interstitial + a cation vacancy
The solvent is an element or compound that is present in ________. - Answers the greatest amount
Decreasing the number of grains or increasing the grain size of a metallic material causes the strength
of the metal to decrease - Answers true
Small angle boundaries formed by edge dislocations are called tilt boundaries. Small angle boundaries
formed by screw dislocations are called twist boundaries. - Answers true
Stacking faults are defects that really interfere with the slip process. Which of the following
statements best describes a stacking fault - Answers A stacking fault represents an error in the
stacking sequence of close packed planes resulting in a small region that has HCP stacking rather than
FCC stacking
Dislocations represent one type of defect in a crystal. Dislocations are responsible for plastic
deformation. What are the two fundamental types of dislocations? - Answers edge and screw
The surface energy of a single crystal depends on the crystallographic orientation with respect to the
surface. - Answers true
Once a system is at a state of equilibrium, a shift from equilibrium may result if one alters which of
the following variables? - Answers - pressure
- composition
- temperature
A solidus line separates which of the following phase fields? - Answers α and L + α
A binary composition vs. temperature phase diagram for an isomorphous system will be composed of
regions that contain which of the following phases and/or combinations of phases? - Answers α,
liduid + α, and liquid
A eutectic reaction involves which of the following phases? - Answers One liquid phase and two solid
phases
"Coring," which represents a form of non-equilibrium solidification, results in variations in the
composition of a solidifying alloy. Coring occurs because of rapid solidification (i.e., the alloy solidifies
faster than
diffusion can occur to equilibrate composition). - Answers true
Name the two general activities that accompany a phase transformation - Answers growth and
nucleation
In precipitation hardening, the solution heat treatment consists of (1) heating the alloy to a
temperature such that all solute atoms are dissolved to form a single-phase solid solution, (2)
quenching to produce a non-equilibrium supersaturated solid solution, and aging at a lower
temperature to form a uniform distribution of small precipitates - Answers true
For most technologically important metal alloys, the usual state or microstructure is: - Answers a
metastable one
Can interstitial atoms ever exhibit unlimited solubility in a metal? - Answers no
Which of the following is not a criterion for unlimited solubility of an alloy? - Answers The atoms or
ions must have a 50% or higher difference in atomic radius size
Dislocations are defects that are responsible for plastic deformation in crystalline solids. Which
of the following correspond to the name of the process by which dislocations move in crystalline
solids? - Answers glide and slip
For a particular crystal structure, the slip direction is that direction in the slip plane having the
________ - Answers highest linear density
Which kind of fracture is associated with the intergranular crack propagation mechanism? - Answers
brittle
In which of the following phenomena do free electrons play a role: thermal conduction or
thermal expansion? - Answers thermal conduction
How do thermal conductivities of single crystals and polycrystalline materials compare? - Answers
Single crystal conductivity is greater.
The typical electrical conductivity value/range for materials are: - Answers Semiconductor 10⁻⁶ to 10⁴
(Ω-m)⁻¹
Metal 10⁷ (Ω-m)⁻¹
