What are the mechanical properties?

yield strength, creep, stiffness, impact, ductility, and fatigue strength

What are the physical properties?

conductivity, temperature, thermal, and environmental

What type of atoms make up a metal?

mostly made of metallic elements

What are typical mechanical properties for a metal?

high electrical conductivity, ductile, strong, shiny

Are metals typically amorphous or crystalline?

crystsalline

Are metals typically single crystal or multi-grained?

multigrain

Do metals have high or low electrical and thermal conductivity?

high

What is a ceramic?

compounds of metallic and non metallic elements

What are typical mechanical properties for a ceramic?

corrosion resistant, low thermal conductivity, brittle, capable of being used at high temperatures

Are ceramics typically amorphous or crystalline?

both

Are crystalline ceramics typically single crystal or multi-grained?

multigrain

Do ceramics have high or low electrical and thermal conductivity?

low

What is a polymer

larger molecules made from smaller molecules in a process called polymerization

What are typical mechanical properties for polymers?

transparent, low electrical and thermal conductivity, and low density

What are typical mechanical properties for thermosets?

low density, brittle, and low electrical conductivity

Are thermosets, thermoplastics, and elastomers typically amorphous or crystalline?

thermosets- amorphous

thermoplastics/elastomers- amorphous or crystalline

Do polymers have high or low electrical and thermal conductivity?

low

What is a composite material?

materials formed mechanically from 2 or more materials

What is a semiconductor

an intermediate between metals and ceramics

How can the electrical properties of a semiconductor be altered?

they can be changed by altering the concentration of minute amounts of impurity atoms

Are semiconductors typically amorphous or crystalline?

cyrstalline

Are crystalline semiconductors typically single crystal or multi-grained?

mostly single crystals

Give some common examples of each material type...

metals, ceramics, polymers, composites, and semiconductors

metals-steel, cast iron, brass, bronze, aluminum alloys

ceramics-alumina, MgO, silica, silicon nitride (brick/glass)

polymers-C, O, N, H, Si, F (furniture/paints/adhesives)

composites- tires, fiberglass, concrete

semiconductors-silicon, germanium (electoronics/detectors)

What is a grain structure?

Found in crystalline materials. It is the portion of a material which has a particular arrangement and a boundary.

What is a mechanical property?

It describes how a material responds to an applied force. It affects how a material can be used and produced.

physical properties are everything else

What is an ionic bond?

Electrons are given/taken to creat full shells.

For compounds with not pure elements.

What is a covalent bond?

Sharing electrons to get 8 valence electrons

What is a metallic bond?

Only occurs in metals when valence electrons are shared.

(a sea of negative electrons)

What are the typical electrical properties for a material with an ionic bond?

good electrical conductors and insulators

What are the typical electrical properties for a material with a covalent bond?

they arent very good electrical conductors

What are the typical electrical properties for a material with a metallic bond?

high electrical and thermal conductors

Are the bond strengths for secondary bonds higher or lower than those for primary bonds?

lower

As the bond strength increases would you expect the melting point to increase or decrease?

increase

As the bond strength increases would you expect the stiffness of a material to increase or decrease?

increase

What is a thermoplastic polymer?

Molecules that are not rigidly linked together but have good ductility and formability

What is a thermoset polymer?

molecules that are rigidly linked together, stronger and more brittle

What is an elastomer polymer?

(rubbers) - are extremely kinked up and partially linked together so that they can be stretched and still recover their original shape.

Which has higher ductility-a thermoset or thermoplastic polymer? Why?

Thermoplastics because the secondary bonding between chains is weaker.

How are ceramic and polymer crystal structures different from metallic crystal structures?

Ceramic and polymer crystal structures are amorphous, while metallic crystals are generally crystalline

When a metallic element and oxygen are combined to form a ceramic what is the ceramic called?

silica - crystalline and amoprhous

How are ceramic crystal structures named?

They are named after a common compound (atom per lattice site)

What is an interstitial?

a defect (an extra atom inserted at the lattice site that is not normal)

Are there any pure elements?

NO!

What is a substitutional solid solution?

when the solute (minor element) replaces the solvent (major element) in a crystal.

What is an interstitial solid solution?

When solute atoms are located in the spaces between the solvent atoms.

What is the solvent-rich phase called in a solid?

matrix

What is the solute-rich phase called in a solid?

precipitate

Rank the following in terms of increasing ductility?
o HCP metal
o BCC metal
o FCC metal

least ductile to most

HCP, BCC, FCC

List four ways that a metal could be strengthened.

1. solid solution stregnthening

2. plastic defomation

3. grain-size strengthening

4. Precipitaion strengthening

What is the mechanism by which the strengthening occurs

grain boundaries

Plastic deformation of a metal increases the strength of the metal. How does this occur?

Because plastic deformation distorts the material until its max yield strength and causes it to have less ductility and more strength.

How are thermoplastic polymers strengthened? Describe the mechanism!

They are reinforced with fibers by aligning the chains to get them stronger and more brittle

Typically as the strength of a metal increases what happens to the ductility?

ductility increases

Practice math problems

ok!