Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Materials Physics > Week 1 > Flashcards

Week 1 Flashcards

(63 cards)

Start Studying
1
Q

What are the four types of bonding?

A

Ionic (Metal - Non-metal),
Covalent (Non metal - Non Metal)
Metallic (Metal - Metal)
Hydrogen (Hydrogen-Element)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the structure of crystalline materials?

A

Atoms arranged in periodic 3D arrays e.g. metals, ceramics, some polymers etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the structure of non-crystalline materials?

A

Atoms have no periodic arrangement e.g. complex structures, rapid cooling. Sometimes called amorphous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why are ordered structures more stable?

A

They tend to be nearer the minimum in bonding energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What two components make up a crystal structure?

A

Crystal lattice + Basis = Crystal Structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the coordination number of atoms/ions/molecules?

A

The number of nearest neighbour or touching atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the atomic packing factor (APF)?

A

The ratio of the volume of atoms in a unit cell to the volume of the unit cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a point coordinate?

A

A lattice position in a unit cell determined by fractional multiples of atomic edge lengths.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are Miller Indices?

A

The reciprocals of the intercepts of the plane of the unit cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the two types of defects?

A

Point defects: Vacancies, Interstitials and Substantial atoms
Large scale defects: Dislocations, Grain boundaries and Surfaces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a vacancy?

A

When an atom is missing from a crystal lattice. The number of vacancies can be determined by the Boltzmann Distribution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an interstatial?

A

When an atom formed by a vacancy stays in the crystal but not at a lattice point.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a substantial impurity?

A

When impurity atoms substitute into the atom’s original lattice, taking the lattice site of one of the atoms from the original material. The size of the SA compared to the other atoms in the lattice determines the force exerted by the substitution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are n-type semiconductors?

A

Semiconductors with an extra electron from the donor atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are p-type semiconductors?

A

Semiconductors with a hole from the acceptor atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the two types of simple dislocations?

A

Edge distortions and Screw distortions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are edge distortions?

A

Terminations of a plane of atoms in the middle of the crystal and can be interpreted as an additional half plane of atoms between two planes. In 2D only edge dislocations are possible.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are screw distortions?

A

Distortions shifted out of the plane of the material so occur in 3D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is slip?

A

The movement of dislocations through a material, typically in the direction of the densest crystal plane. Since dislocations only break a few bonds at a time, it uses much less energy than if the entire lattice plane was moving

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are grains?

A

Regions in a material of different orientations, that were formed separately or built up from strain in different directions over time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are monocrystalline and polycrystalline materials?

A

Monocrystalline: A material with a single grain
Polycrystalline: A material with lots of crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a grain boundary?

A

A point where two grains meet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is a misorientation angle?

A

The angle between two grains that characterise grain boundaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are high/low angle grain boundaries?

A

High: MOA of less than 15 degrees and considered a collection of isolated and distinct dislocations
Low: MOA of more than 15 degrees and have a poorer fit resulting in a disordered region at the interface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is a crystal phase?
A region of a material that has a defined crystal structure and composition
26
How can new crystal phases form?
Changing the amount of an element in a material, adding stress or temperature
27
Can there be multiple phases in a material?
Yes but they must be different in composition/structure
28
What is the matrix phase?
The one with the highest composition or the one that presents across the whole material. Others are precipitates or inclusions
29
What are surface atoms?
Atoms that have electrons not involved in bonding so have higher energy called the surface energy.
30
What are the four ways defects can form?
- During crystal formation - Due to heat and stress - Irradiation - Corrosion
31
What is stress?
Force applied per unit area
32
What is strain?
Change in length per unit length
33
What are the four types of stress?
Tensile stress, compressive stress, shear stress and torsional stress
34
What is uniaxial stress?
Stress in the direction perpendicular to the cross section
35
What can be used to measure strain?
A strain gauge which is attached to a polished side of a sample and measures the difference between compression and tension when the pattern on the gauge is alternated. As the sample stretches is electrical resistance will increase which is used to measure strain.
36
What does Young's Modulus measure?
The stiffness/springiness of a material
37
What is Hooke's stiffness?
The product of Young's modulus and the specimen geometry
38
What is a stiff material?
One with a high Young's modulus and changes its shape only slightly under elastic loads
39
What is a flexible material?
One with a low Young's modulus and changes its shape considerably under elastic loads
40
How does a strong material differ from a stiff material?
A stiff material requires high loads to elastically deform it but a strong material requires high loads to permanently deform and break it
41
What is the elastic region?
The region of deformation where strain is proportional to stress
42
What is Poisson's ratio?
The relationship between the strain in the axial and transverse directions
43
What is torsion?
The twisting of a material about its longitudinal axis due to torque
44
What is volumetric strain?
Where a material has stress applied from all directions e.g. pressure at the bottom of the sea
45
What are the differences between compressive and tensile stress?
Compressive is negative and samples buckle before failure and tensile is positive and samples elongate or neck and then fracture
46
What are the stress characteristics of stone?
It has good compressive stress but poor tensile stress
47
How does an arch hold its structure?
Each stone is in compressive stress with its neighbours and any tensile component is converted into compression down the columns below the arch
48
What gives an arrow from a bow its force?
The tension of the bow string due to the string being lighter and transferring more power to the arrow than the limbs.
49
What is strain energy?
The energy beneath a stress-strain graph
50
What is the limit of proportionality?
The point at which linear behaviour ends
51
What is yield strength?
The point at which the material ceases to behave elastically and begins to deform in a manner that cannot be recovered
52
What is plastic deformation?
When a material deforms in a way that is not proportional and reversable
53
What is a ductile material?
One that sustains significant plastic deformation before fracture
54
What is a brittle material?
One that has no significant plastic deformation before fracture
55
What are the characteristics of ductile steel?
Elastic and linear up to its proportional limit but can elastically deform without permanent damage up to its yield strength. It will then plastically deform and can resist more stress up to its ultimate tensile strength after which it loses strength and fails
56
What is stiffness?
How much elastic deformation a material experiences under stress
57
What is ultimate tensile strength (UTS)?
The maximum stress a ductile material can experience before it weakens to failure
58
What does elongation to failure measure?
The ductility of a material or the amount of strain it can experience before fracture in tensile testing
59
What is hardness?
Resistance to localised plastic deformation
60
What is Mohs hardness?
A scale of hardness across all materials from 1 - 10
61
What is toughness
The energy absorbed during fracture of a material
62
What are polymers and elastomers?
Polymers are organic solids made of carbon chains that are light, have a low modulus and are easy to shape. Elastomers are polymers with low stiffness, very large recoverable shape change and are tough
63
What are hybrids?
A combination of two or more other materials to create properties that are otherwise unattainable in a single material

Materials Physics (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions