Materials Science Chapters 1-6, 17

If the carbon content in common steel increases, the hardness then…

Increasing the temperature generally _________ electrical resistance.

Deformation in a material typically ________ electrical resistance.

The efficacy of heat conduction __________ as porosity increases.

When in this structure, electron position is described in terms of proprietary density, and the aspects of this are determined by quantum numbers.

T or F: Most elements have unstable configurations.

1 - e(-0.25 * ΔEN²)

Atomic arrangement of a material that has periodic, 3D arrays of molecules.

Atomic arrangement of a material that has any non-periodic arrangement

Metals have dense atomic packing because…

The coordination number (C#) is the number of…

SCC Coordination Number

SCS Radius (where a is edge length)

SCS Atoms per unit cell

SCS Atomic Packing Factor

BCC Coordination Number

BCC atoms per unit cell

BCC Atomic Packing Factor

BCC Radius (where a is edge length)

FCC Coordination Number

FCC Atoms per unit cell

FCC Radius

HCP atoms per unit cell

Ideal ratio for c:a in HCP material structure.

HCP Radius is actually dependent on the how many factors?

Think: there are different molecules in this structure

What atomic facters determine crystal structure in ceramics?

When the ratio of cation:anion increases, the coordination number….

Bond hypridization is possible where there is significant ___________ bonding.

The Percent Ionic Character is what percent of atoms becomes…

The most common elements on earth are…

A polymorphic form of quartz, a type of ceramic. Known as (SiO₂)

When SiO₄ is bound to other stuff, we get….

Bonds within silicates do what two things?

Structure of glass.

Fused silica (SiO₂) with no impurities; noncrystalline stucture.

Tetrahedrally structured carbon.

Layered parallel-hexagonal arrayed carbon

Describe the structure of graphite

When property values depend on direction; observed in single crystals.

Polycrystals where properties have random orientation.

Polycrystals where properties are textured.

When there are 2+ structures for the same material.

Carbon has multiple forms, such as diamond and graphite. This is an example of the trait…

A hydrocarbon where each carbon is singly bonded to four other atoms.

A hydrocarbon where some carbon is doubly/triply bonded to four other atoms.

The property describing that two compounds with the same chemical formula may have multiple different structures.

The average number of repeat monomers per chain.

Grains that are roughly the same dimension in all directions after solidification.

Grains that are elongated in one direction after solidification.

Something added to a substance during solidification to make smaller, more uniform, equiaxed grains.

Heat treating polymers causes % crystallinity to…

Polymers are usually a mix of straight regions (crystalline) and squiggly regions called _____ regions.

A type of crystals that, in polymers, are only for slow and carefully controlled growth rates.

Polymer semi-crystalline structure that alternates chain-folded crystallites and amorphous regions.

Polymer spherulite structures have relatively ______ growth rates.

Each spherulite in polyethylene can look like what shape?

Two steps of solidification in solids.

The slight atomic disorder in grain boundaries leads to what two attributes?

Dimension of Defect:

Vacancies

Dimension of Defect:

• 0 (point)

• 1 (linear)

• 2 (interfacial)

Interstitial atoms

Dimension of Defect:

• 0 (point)

• 1 (linear)

• 2 (interfacial)

Substitutions

Dimension of Defect:

• 0 (point)

• 1 (linear)

• 2 (interfacial)

Dislocations

Dimension of Defect:

• 0 (point)

• 1 (linear)

• 2 (interfacial)

Grain boundaries

What point defect of a metal does the picture describe?

What point defect of a metal does the picture describe?

In metals, each ____________ is a potential vacancy

In ceramics, vacancy point defects can happen with _________.

• Cations

• Anions

• Cations and anions

In ceramics, interstitial point defects can happen with _________.

• Cations

• Anions

• Cations and anions

Note: one option is observed more normally, because the other is usually too large

Conditions for substitutions in metals (Hume-Rothery Rules)

A polymer linear dislocation where part of the polymer extends from the base in a twisting manner

A polymer point defect where the chain drops off the boundary and ends.

A polymer point defect where the typically straight chain starts warping and wiggling.

A polymer point defect where the chain trails off of the base and eventually returns.

A polymer point defect where the chain stops before it should.

A polymer point defect where two loops of the chain connect horizontally

In a screw dislocation, the measure of lattice distortion (Burger’s vector) is ________ to the dislocation line.

A plane dislocation that occurs when an extra half-plane of atoms is inserted into the base structure, perpendicular to the dislocation line.

Dislocations _____ when stresses are applied and results in ________ deformation

Mirror reflections of atom positions of one side is a twin to the other; an interfacial defect

These interfacial faults occur when there is an error in the planar stacking sequence. For example, ABABC instead of ABCABC

Catalytic reactions normally occur at….

Grain boundaries are (more/less) susceptible to etching.

Number of Grains Per Inch² at 100x magnification.

Metallographic scopes often use this type of light to increase contrast.

The best resolution for an optical microscope is….

The best resolution for an electron microscope is…

The best possible magnification for an electron microscope is…

The best possible magnification for an optical microscope is…

Electron beams in an electron microscope are focused by what type of lenses?

Type of microscopy where surface atoms are imaged using a tiny probe that tapers to a single atom; atoms can be rearranged by pushing them with a tip.

Three types of dislocation imperfections.

Gases and liquids have this diffusion mechanism.

Diffusion of atoms of one material into another.

Atomic migration in a pure metal

The rate of vacancy diffusion depends on…

Interstitial diffusion is (faster, slower) than vacancy.

A type of interstitial diffusion where the outer surface is selectively hardened by diffusing carbon atoms into the surface.

Case hardening diffuses what atoms into the surface of the material?

Diffusion of very small concentrations of atoms of impurity (e.g. phosphorous) into the semiconductor silicon.

The target of diffusion in doping is what material?