Chapter 1

Question 1

To select appropriate materials and processing techniques for specific applications engineers must…

Answer 1

1. Have knowledge of materials properties
2. Understand the structure-property relationships

Question 2

What’s an example of processing? What does it affect?

Answer 2

1. Cooling rate of steel from high temperature
2. Structure (microstructure)

Question 3

What does structure affect?

Answer 3

Properties

Question 4

What are three properties of metals?

Answer 4

1. Strong and ductile
2. High thermal & electrical conductivities
3. Opaque and reflective

Question 5

What are polymers made from? What are three properties of polymers/plastics?

Answer 5

Compounds of non-metallic elements

1. Soft, ductile, low strengths, low densities
2. Low thermal & electrical conductivities
3. Opaque, translucent or transparent

Question 6

What are ceramics made from? What are three properties of ceramics?

Answer 6

Compounds of metallic & non-metallic elements (oxides, carbides, nitrides, sulfides)

1. Hard and brittle
2. Low thermal & electrical conductivities
3. Opaque, translucent, or transparent

Question 7

What are the 6 material properties?

Answer 7

METMOD: Mechanical, electrical, thermal, magnetic, optical, deteriorative

Question 8

What happens if you increase the carbon content of steel (iron)?

Answer 8

It increases the hardness of

Question 9

What three factors increase the electrical resistivity for copper?

Answer 9

1. Increasing temperature
2. Increasing impurity content
3. Deformations

Question 10

What is thermal conductivity?

Answer 10

measure of the material’s ability to conduct heat

Question 11

What does increasing the impurity content do to thermal conductivity?

Answer 11

Decreases thermal conductivity

Question 12

Are highly porous materials good or poor conductors of heat?

Answer 12

Poor conductors

Question 13

Why do ceramic fibers have low thermal conductivity?

Answer 13

Significant void space

Question 14

What are the two magnetic properties?

Answer 14

Magnetic storage and magnetic permeability

Question 15

What is magnetic storage?

Answer 15

Recording medium is magnetized by recording write heat

Question 16

What is magnetic permeability?

Answer 16

Measure of magnetization produced in a material in response to an applied magnetic field.

Question 17

What is magnetic storage?

Answer 17

Magnetic storage or magnetic recording is the storage of data on a magnetized medium.

Question 18

How do you make iron a better recording medium?

Answer 18

Add 3 atomic % Si

Question 19

What affects optical properties?

Answer 19

The light transmittance of some materials depend on their structural characteristics.

Question 20

What does the aluminum oxide single crystal look like? why?

Answer 20

optically transparent because of a high degree of perfection

Question 21

what does the aluminum oxide polycrystalline material look like? why?

Answer 21

optically translucent because it has many small grains

Question 22

what does the aluminum oxide polycrystalline material look like?

Answer 22

it’s optically opaque since it has some porosity

Question 23

What does it mean for a material to be a single crystal?

Answer 23

the arrangement is periodic in all of the space of any size

Question 24

Why are some crystals translucent?

Answer 24

there are grain boundaries that separate each section of crystal (each section is a single crystal)

Question 25

What would happen if a steel bar was stressed and immersed in sea water?

Answer 25

It would form stress- corrosion cracking

Question 26

Why does stress-corrosion cracking form?

Answer 26

When you put stress into something it has high energy to it cracks to get back to low energy

Question 27

What kind of material has the most deteriorative properties? why?

Answer 27

metals since they're the most reactive with oxygen

Question 28

What is the relationship between heat treating and stress-corrosion cracking?

Answer 28

Crack growth is diminished by heat treating

Question 29

Why does heat treatment work?

Answer 29

If you have a deformed metal and you heat it, energy is high, so atoms can be moved without cracking a lot

Question 30

What are the 4 material requirements for artificial joins?

Answer 30

1. Biocompatible-- minimum rejection by surrounding body tissue 2. Chemically inert to body fluids 3. Mechanical strength to support forces generated 4. Good lubricity and high wear resistance between articulating surfaces

Question 31

Parts of an artificial hip replacement Femoral stem? Head (ball)? Shell? Liner?

Answer 31

Femoral stem: inserted into the top of the hip bone (femur) Head (ball): affixed to femoral step Shell: attached to the pelvis Liner: into which head fits

Question 32

Materials for Artificial Hip Replacement Femoral stem? Head (ball)? Shell? Liner?

Answer 32

Femoral stem: titanium or CoCrMo alloy Head (Ball): CoCrMo alloy or Al2O3 (ceramic) Shell: titanium alloy Liner: polyethylene (polymer) or Al2O3 (ceramic)

Question 33

With regards to the design, production, and utilization of materials, what are the four elements to consider?

Answer 33

Processing, structure, properties, and performance

Question 34

What elements are metals composed of? Ceramics? Polymers? Composites?

Answer 34

Metals: Metallic elements Ceramics: Compounds between metallic and nonmetallic elements Polymers: Compounds composed of carbon, hydrogen, and other nonmetallic elements. Composites: Two different material types.

Question 35

What is an important property of semiconductors?

Answer 35

Having electrical conductivities intermediate between those of conductors and insulators

Question 36

What are smart materials?

Answer 36

those that sense and respond to changes in their environments in predetermined manners

Question 37

What is the subatomic structure?

Answer 37

involves electrons within the individual atoms, their energies and interactions with the nuclei

Question 38

What is atomic structure?

Answer 38

Relates to the organization of atoms to yield molecules or crystals

Question 39

What is nanostructure?

Answer 39

Deals with aggregates of atoms that form particles (nanoparticles) that have nanoscale dimensions (less than 100 nm)

Question 40

What is microstructure?

Answer 40

Those structural elements that are subject to direct observation using some type of microscope (structural features having dimensions between 100 nm and several millimeters)

Question 41

What is macrostructure?

Answer 41

Structural elements that may be viewed with the naked eye (with scale range between several millimeters and on the order of a meter)

Question 42

What is a property?

Answer 42

A material trait in terms of the kind and magnitude of response to a specific imposed stimulus

Question 43

What is a mechanical property?

Answer 43

relate deformation to an applied load or force, examples include elastic modulus (stiffness), strength, and resistance to fracture

Question 44

What is an electrical property?

Answer 44

A stimulus is an applied electric field; typical properties include electrical conductivity and dielectric constant

Question 45

What is a thermal property?

Answer 45

Are related to changes in temperature or temperature gradients across a material; examples of thermal behavior include thermal expansion and heat capacity

Question 46

What is a magnetic property?

Answer 46

The responses of a material to the application of a magnetic field; common magnetic properties include magnetic susceptibility and magnetization

Question 47

What are optical properties?

Answer 47

The stimulus is electromagnetic or light radiation; index of refraction and reflectivity are representative optical properties

Question 48

What are deteriorative characteristics?

Answer 48

Relate to the chemical reactivity of materials; for example, the corrosion resistance of metals