Metallurgy Test 1 Questions

The packing factor for the simple cubic structure is: A. 0.52 B. 0.68 C. 0.74 D. 1.00

0.52

The packing factor for the BCC crystal structure is: A. 0.52 B. 0.68 C. 0.74 D. 1.00

0.68

The packing factor (packing efficiency) of the FCC crystal structure is: A. 0.52 B. 0.68 C. 0.74 D. 1.00

0.74

The packing factor (packing efficiency) of the HCP crystal structure is: A. 0.52 B. 0.68 C. 0.74 D. 1.0

0.74

The number of atoms or lattice points fully-contained in a simple cubic unit cell is: A. 1 B. 2 C. 3 D. 4 E. 5 F. 14

1

The fraction of a corner atom that lies within a given unit cell is: A. 1/8 B. 1/4 C. 1/3 D. 1/2

1/8

Structures with stacked close-packed planes have __ nearest neighbor atoms (i.e. the coordination number). A. 6 B. 8 C. 10 D. 12 E. Can't determine

12

The number of atoms or lattice points fully contained in a BCC unit cell is: A. 1 B. 2 C. 3 D. 4 E. 5 F.9

2

If a material contains 8 grains per square inch at 100x magnification, it would have an ASTM grain size number of: A. 2 B. 3 C. 4 D. 5 E. 6

4

The number of atoms or lattice points fully-contained in the FCC unit cell is: A. 1 B. 2 C. 3 D. 4 E. 5 F. 14

4

An FCC crystal is comprised of atoms with an atomic radius of 1.59 angstroms. The lattice parameter, a*o, for this crystal would be __ angstroms. A. 3.18 B. 3.67 C. 4.5 D. 6.36

4.5

The coordination number for the simple cubic arrangement is: A. 4 B. 6 C. 8 D. 12 E. 14

6

In any cubic lattic, corner atoms are shared by ___ unit cells: A. 2 B. 4 C. 6 D. 8 E. 12

8

In the BCC crystal structure, the coordination number is: A. 4 B. 6 C. 8 D. 12 E. 14

8

A shorthand notation for all cube edges would be: A. <100> B. <110> C. <111> D. <123>

<100>

In the FCC crystal structure, the close-packed directions (directions of atom touching) have the form: A. <100> B. <110> C. <111> D. <123>

<110>

In the BCC crystal structure, atoms touch in which crystallographic directions? A. <100> B. <110> C. <111> D. <123>

<111>

A slip system consists of: A. A dislocation and a vacancy B. A direction and a plane of possible dislocation movement C. A dislocation and an interstitial

A direction and a plane of possible dislocation movement

The stacking sequence for the HCP crystal structure is: A. ABABAB B. ABCABC

ABABAB

The stacking sequence for the FCC crystal structure is: A. ABABAB B. ABCABC

ABCABC

"Design" involved precisely defining: A. What we want to produce B. The conditions it will see in use C. What properties it must possess D. All of the above

All of the above

Met 2110 will develop the relationships between: A. Structures and properties B. Properties and processing C. Properties and performance D. All of the above

All of the above

The "design requirements" that must be considered for a product or component are: A. Geometric requirements B. Manufacturing requirements C. Mechanical Properties D. All of the above

All of the above

A mathematical description of directions and surfaces within a crystal is useful because: A. Deformation occurs on particular planes in preferred directions B. Certain properties may vary with direction C. Atom arrangement varies with directions and along various surfaces D. All of these

All of these

Diffusion is require for or useful in: A. Eliminating non-uniform chemistry B. The heat treatment of metal C. Altering surface chemistry D. All of these

All of these

Materials that can exist in more than one crystal structure (depending upon the conditions of temperature and pressure) are called polymorphic (many-sturcutred). Another term for this feature is: A. Amorphous B. Allotropic C. Anisotropic

Allotropic

Properties that assume different values when measured in different directions are: A. Allotropic B. Anisotropic C. Isotropic D. Polymorphic

Anisotropic

In Shmid's Law, t=ocosycosø, the symbol 0 is known as the: A. Resolved sheer stress B. Critical resolved shear stress C. Applied Stress

Applied stress

As a result of the __ crystal structure, iron and steel at room temperature exhibit unusually high strength: A. BCC B. FCC C. HCP

BCC

The critical resolved shear stress is greatest in ___ materials. Hence it provides the highest strength. A. HCP B. BCC C. FCC

BCC

In the BCC unit cell, the atoms are "touching" along the: A. Cube edges B. Face diagonals C. Body diagonals

Body diagonals

When a crystalline solid is heated to a high temperature, the atoms: A. Can move about within the crystalline solid B. Remain fixed in lattice locations within the crystalline solid

Can move about within the crystalline solid

These materials can provide electrical and thermal insulation at high operating temperatures: A. Metals B. Ceramics C. Polymers

Ceramics

These materials exhibit both good strength and good ductility (formability) A. Metals B. Ceramics C. Polymers

Ceramics

The number of immediately adjacent (i.e. touching) atoms to a given atom is called the: A. Neighbor number B. Packing Factor C. Coordination Number

Coordination Number

The bonds between carbon-carbon and carbon-hydrogen (common within polymers) are of this type: A. Ionic B. Covalent C. Metallic D. VanderWaals

Covalent

The restricted number of "neighbors" leads to directional bonding and low densities in this type of bonding: A. Ionic B. Covalent C. Metallic D. VanderWaals

Covalent

The stress required for a dislocation to move is called the: A. Applied stress B. Critical resolved shear stress C. Burger's Stress

Critical resolved shear stress

The properties of engineering metals are primarily dependent upon and controlled by the: A. Chemical purity B. Crystal structure C. Crystal defects

Crystal defects

The activity sequence for manufactured products generally begins with: A. Design B. Manufacture or Fabrication C. Material Selection D. Process Selection

Design

Mechanical and nuclear engineering are generally considered to be this type of discipline: A. Design Engineering B. Support Engineering

Design Engineering

A high activation energy means that diffusion is A. Difficult B. Easy

Difficult

Metal deformation or ductility is the result of movement of this type of defect: A. Vacancy B. Dislocation C. Interstitial D. Grain boundary

Dislocation

The strength of engineering metals is significantly lower than the theoretical strength (such as 30,000 psi and not 3 million). The defect responsible for this is called a(n): A. Vacancy B. Dislocation C. Interstitial D. Grain boundary

Dislocation

This type of defect responsible for the increased strength obtained during strain hardening (deformation strengthening) is the: A. Dislocation B. Grain boundary C. Substitutional point defect

Dislocation

Line imperfections in a crystalline solid are called: A. Vacancies B. Dislocations C. Interstitial D. Grain boundaries

Dislocations

When a material is heated to elevated temperature, the diffusing atoms will tend to: A. Distribute uniformly throughout the host material B. Form concentrated clusters in the host material

Distribute uniformly thorughout the host material

When iron cools from red-heat to room temperature, it changes from FCC to BCC. Because of this change and the different packing factors associated with these structures, iron _____ during this change. A. Contracts B. Expands

Expands

Aluminum, copper, silver, and gold are "soft, weak, and extremely ductile." These properties are characteristic of metals with this crystal structure: A. BCC B. FCC C. HCP

FCC

Materials with this structure are very ductile, since it has four different slip planes and three slip directions in each-for twelve slip systems: A. HCP B. BCC C. FCC

FCC

In the FCC unit cell, the atoms are "touching" along the: A. Cube edges B. Face diagonals C. Body diagonals

Face diagonals

Crystalline defects are generally classified by their: A. Geometry B. Location C. Size

Geometry

In a polycrystalline material, the surfaces that are created where the individual crystals meet are called: A. Vacancies B. Twin boundaries C. Stacking faults D. Grain Boundaries

Grain boundaries

Magnesium and zinc die castings (such as Hot Wheels cars), are characteristically brittle. This is because these metals have the ___ crystal structure. A. BCC B. FCC C. HCP

HCP

Materials with this structure tend to be brittle because there is only one identifiable slip plane, and it may not be favorably oriented: A. HCP B. BCC C. FCC

HCP

Because of their metallic bonding, metals would like to have a _______ coordination number and a _________ packing factor: A. Low, low B. Low, high C. High, low D. High, high

High, high

In the cubic systems, the (`110) plane and the (1`10) plane (plane and its negative) are: A. Identical B. Perpendicular

Identical

If we increase the temperature, we would expect the diffusion coefficient to : A. Decrease B. Remain unchanged C. Increase

Increase

If we increase the temperature, the flux or the amount of atom movement will: A. Remain unchanged B. Increase exponentially C. Increase linearly

Increase exponentially

Adding crystalline imperfections to a metal lattice almost always ___ the strength and ___ the ductility. A. Decreases, increases B. Decreases, decreases C. Increases, decreases D. Increases, increases

Increases, decreases

If a plane is parallel to a coordinate axis, the intercept is considered to be: A. Zero B. One C. Infinity

Infinity

Carbon atoms are much smaller than iron atoms. We would expect carbon to move in iron by: A. Vacancy diffusion B. Interstitial diffusion

Interstitial diffusion

Since none of the crystal structures have 100% packing efficiency, smaller atoms may fit into spaces between the host atoms. These locations and the atoms lying there are called: A. Vacancies B. Interstitials C. Substitutionals

Interstitials

Diffusion is more difficult in ___ bonded materials. A. Ionic B. Metallic

Ionic

In this type of bonding, the bonding electrons are "captive to atoms" (low conductivity) A. Ionic B. Covalent C. Metallic D. VanderWaals

Ionic

Two different types of atoms (an electron donor and an electron receiver) are required in this type of bonding: A. Ionic B. Covalent C. Metallic D. VanderWaals

Ionic

When a magnesium atom gives up two electrons to an oxygen atom, resulting in the formation of MgO, the type of atomic bonding must be: A. Ionic B. Covalent C. Metallic D. VanderWaals

Ionic

Compared to a metal with an ASTM grain size of 6, a material with a grain size number of 4 would have ____ crystals and would be _____. A. Smaller, weaker B. Smaller, stronger C. Larger, weaker D. Larger, stronger

Larger, weaker

A collection of ordered points space is called a _____. A. Crystal B. Lattice C. Unit Cell

Lattice

Lengths are measured in units of ___ in a crystallographic coordinate system: A. Lattice parameters B. Nanometers C. Microns D. Angstroms

Lattice Parameters

The Met 2110 course will focus on this stage of the manufacturing sequence: A. Design B. Manufacture or Fabrication C. Material Selection D. Process Selection

Material selection

Dislocations move most easily and impart ductility in materials with this type of bonding: A. Metallic B. Ionic C. Covalent

Metallic

In this type of bonding, the valence electrons are free to "wander" throughout the structure (high conductivity): A. Ionic B. Covalent C. Metallic D. VanderWaals

Metallic

Materials bonded by this type of bond can exhibit both high strength and high ductility: A. Ionic B. Covalent C. Metallic D. VanderWaals

Metallic

These materials offer good electrical and thermal conductivity: A. Metals B. Ceramics C. Polymers

Metals

The efficiency of filling available space (% occupied) can be evaluated by computing the: A. Unit cell volume B. Packing Factor C. Coordination number

Packing Factor

For an edge dislocation, the Burger's vector is ___ to the dislocation line: A. Perpendicular B. Parallel

Perpendicular

These materials are often called "plastics" A. Metals B. Ceramics C. Polymers

Polymers

These materials typically have the lowest strength, but are light weight: A. Metals B. Ceramics C. Polymers

Polymers

These materials would be the least suitable for use at elevated temperatures: A. Metals B. Ceramics C. Polymers

Polymers

A material with lots of little crystals would be expected to have ___ electrical conductivity than the same metal with larger crystals. A. Better B. The same C. Poorer

Poorer

If the temperature is increase, the value of the activation energy, Q, will A. Decrease B. Remain unchanged C. Increase

Remain unchanged

In Schmid's Law, t=ocosy cosø, the symbol t is known as the: A. Resolved sheer stress B. Critical resolved shear stress C. Applied stress

Resolved shear stress

In a cubic system, the [`110] direction and the [1`10] direction (direction and its negative where '1 is 1 with the line over it) are: A. Identical B. Perpendicular C. Same line, opposite sense

Same line, opposite sense

For an edge dislocation, the dislocation line and Burger's vector combine to define a: A. Slip Plane B. Screw dislocation C. Stacking fault

Slip plane

When we introduce interstitial or substitutional point defects into a metal crystal, the increase in strength that occurs is known as: A. Grain size strengthening B. Solid solution strengthening C. Strain hardening

Solid solution strengthening

If a layer is out of sequence in the ABCABC stacking (such as ABCABABC), the defect is called a: A. Vacancy B. Grain boundary C. Stacking fault D. Twin boundary

Stacking Fault

Zinc atoms and copper atoms are approximately the same size. If a zinc atom occupies a lattice point in a crystal of nearly pure copper, the "defect" is called a(n): A. Vacancy B. Interstitial C. Substitutional

Substitutional

Materials engineering is generally considered to be this type of discipline: A. Design Engineering B. Support Engineering

Support Engineering

In Fick's First Law, J=-D(dc/dx), the term "D" represents: A. The diffusion coefficient B. The temperature C. The flux of atoms D. The concentration gradient

The diffusion coeffecient

In Fick's First Law, J=-D(dc/dx), the term "J" represents: A. The diffusion coefficient B. The temperature C. The flux of atoms (# crossing an area in a given time) D. The concentration gradient

The flux of atoms

The smallest volume of a lattice that retains all of its characteristics is called the: A. Lattice Point B. Unit Cell C. Nano-volume

Unit cell

The defect that occurs when an atom is missing from a lattice point is called a(n): A. Vacancy B. Interstitial C. Substitutional

Vacancy

The two most common mechanisms for diffusion are: A. Vacancy and interstitial B. Vacancy and ring C. Vacancy and intersitialcy D. Intestitial and Ring

Vacancy and intersitital

Zinc atoms are about the same size as copper atoms. We would expect zinc atoms to move in copper by: A. Vacancy diffusion B. Interstitial diffusion

Vacancy diffusion

In this type of bonding, the bonding is between molecules, not atoms: A. Ionic B. Covalent C. Metallic D. VanderWaals

VanderWaals

This is the weakest of the four types of bonding: A. Ionic B. Covalent C. Metallic D. VanderWaals

VanderWaals

For diffusion processes, the activation energy, Q, is a measure of: A. The thermal energy required to raise the temperature of the material by one degree B. The distance an atom will diffuse in a given time C. The number of atoms passing through a given area in a given time D. What is required to cause an atom to move from one location to another

What is required to cause an atom to move from one location to another

According to Schmid's Law, the most favorable condition for slip to occur is: A. Y=90 degrees B. y = ø = 45 degrees C. ø=90 degrees

y=ø=45 degrees

The close-packed planes in the FCC crystal structure have the form: A. {100} B. {110} C. {111} D. {123}

{111}