Materials 1 Flashcards

NOT COMPREHENSIVE! Just some things that I have trouble remembering.

1
Q

How to derive engineering vs true stress relationship

A

Constant Volume assumption

V = A * L and σ = P/A

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2
Q

How to derive engineering vs true strain relationship

A

Integrate ΔL/L

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3
Q

What does %RDA stand for?

A

Percentage Reduction in Area

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4
Q

Poisson’s Ratio for constant volume

A

v = 0.5

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5
Q

Units of P in hardness tests

A

kg

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6
Q

Stress Amplitude

A

Half the range

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7
Q

Stress Ratio

A

σ(min) / σ(max)

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8
Q

Sensitivity to creep

A

Operating temp / Melting temp

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9
Q

Bonds in Semiconductors

A

Covalent

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10
Q

Bonds in Polymers

A

Covalent and Secondary

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11
Q

Bonds in Metals

A

Metallic

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12
Q

Bonds in Ceramics

A

Ionic and Covalent

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13
Q

Young’s Modulus equation based on atomic structure

A

E = (2q^2) / (π* ε* r^4)

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14
Q

1 Mole

A

6.02 x10^23

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15
Q

Selection metric for Maximum Elastic Energy Storage

A

M = UTS^2 / E

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16
Q

Ductile failure shape

A

Cup and Cone

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17
Q

Ductile failure energy absorbtion

A

High energy absorbtion

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18
Q

Brittle failure shape

A

Flat

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19
Q

Brittle failure energy absorbtion

A

Low energy absorbtion

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20
Q

Stages of creep (ε/t graph)

A

Initial elastic strain (linear, steep), primary creep (concave), steady-state creep (linear), tertiary creep (convex, accelerating), rupture

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21
Q

Why is creep temperature dependent?

A

Creep is due to the diffusion of atoms

22
Q

Stress amplitude σa for first fatigue test

23
Q

Typical fatigue testing frequencies

24
Q

Electrons in outer shell of metals

A

Nearly Empty

25
Electrons in outer shell of non-metals
Nearly Full
26
Non-directional Bonds
Ionic, Metallic
27
Directional Bonds
Covalent
28
Signs for bond potential energy
Attraction -ive Repulsion +ive
29
Signs for bond forces
Attractive +ive Repulsive -ive
30
Define Crystal
Homogenous solid. Atoms/molecules arranged in a regular repeating pattern.
31
Material with Simple Cubic Structure
Polonium
32
Materials with Hexagonal Close Packed (HCP) structure
Magnesium, Titanium, Beryllium
33
Materials with Face Centred Cubic (FCC) structure
Aluminium, Copper, Lead, (Iron between 910-1400 ℃)
34
Materials with Body Centred Cubic (BCC) structure
Chromium, Tungsten, Iron (Below 910 and above 1400 ℃)
35
HCP Lattice Slip Systems
1x3 = 3
36
FCC Lattice Slip Systems
3x4 = 12
37
BCC Lattice Slip Systems
2x6 = 12
38
Critically resolved shear stress τ(crss)
σ * (cos(Φ) * cos(λ))max
39
Minimum stress to cause yielding in a single crystal
σ = 2τ(crss)
40
α - Fe is called...
Ferrite
41
Ferrite Structure
BCC
42
γ - Fe is called...
Austenite
43
Austenite Structure
FCC
44
δ - Fe Structure
BCC (from 1400 to melting temp)
45
Fe3C is called...
Cementite
46
Cementite Carbon Content
6.7% by weight
47
"Eutectoid" carbon content for steel
0.8% C
48
Eutectoid Structure (α + Fe3C) is called...
Pearlite
49
Eutectoid α Phase Carbon Content
0.022% C
50
Creep temp for metals
0.3 Tm
51
Creep temp for ceramics
0.4 Tm
52
How to increase Tg
Increase Chain Stiffness Increase Bond Strength Increase Molecular Weight