AS - materials and components Flashcards
0
Q
Ductility means
A
The ability to be drawn into wires
1
Q
Plasticity means
A
The ability to return shapes to their original shape
2
Q
Hardness means
A
The ability to withstand scratching
3
Q
Brittleness means
A
The tendency to fracture under stress
4
Q
Malleability means
A
The ability of a metal to be deformed by compression without being torn or cracked
5
Q
Ferrous is when
A
A metal contains iron
6
Q
Mild steel properties include
A
Ductile, tough, malleable, high tensile strength, easily worked, rusts
7
Q
Rust is
A
Oxidation
8
Q
More carbon added to steel makes it
A
Harder
9
Q
Ferrous metals include
A
Cast iron/steel (mild+Carbon)
10
Q
Aluminium a properties include
A
Lightweight, corrosion resistant, good conductor, malleable, has an oxide layer
11
Q
What ore is aluminium obtained from
A
Bauxite ore
12
Q
What are some uses of aluminium
A
Drinks cans, aeroplanes
13
Q
Properties of copper include
A
Ductility, malleable, great conductor, corrosion resistant
14
Q
Uses of copper include
A
Wiring and circuitry
15
Q
What happens when you work copper? How can you reduce this effect?
A
It hardens, soften it by annealing
16
Q
Properties of zinc include
A
Easily worked, corrosion resistant
17
Q
What happens when zinc is worked? And what is zinc used for?
A
It becomes increasingly brittle, it’s used for galvanising
18
Q
Examples of non-ferrous metals are
A
Aluminium, copper, zinc
19
Q
Examples of alloys are
A
Stainless steel, duralumin, brass
20
Q
What is stainless steel composed of
A
Chromium, nickel, steel
21
Q
What is duralumin composed of
A
Aluminium copper manganese
22
Q
Brass is composed of
A
Copper and zinc
23
Q
Properties of stainless steel include
A
Corrosion resistant, hard, aesthetically pleasing
24
Examples of stainless steel are
Cutlery/kitchen utensils
25
Properties of duralumin include
Lightweight, strong, ductile, malleable, excellent to work with
26
Examples of duralumin include
Aircraft industry
27
What happens to duralumin over time
It hardens
28
Properties of brass include
Corrosion resistant, works very well, good thermal+electrical conductivity
29
Examples of brass in use include
Plug sockets, central heating
30
Examples of thermoplastic polymers include
Acrylic, PET, H/LDPE,PVC,PP,ABS, PS
31
Positives of acrylic are
```
Comes in colours
Stiff
Hard
Durable
Good insulator
```
32
Negatives of acrylic
Brittle
Scratches easily
Splinters easily
33
Examples of acrylic
Lighting
Cd cases
Car lights
34
PET positives are
Chemical resistant
High impact resistance
Tensile strength
35
PET negatives are
Can discolour
| If used for food packaging the food has to be treated to prevent problems in taste
36
Example of PET in use
Fizzy drinks bottles
37
Positives of HDPE
Good electrical insulator
Chemical+impact resistance
Flexible
38
Negatives of HDPE
Colour fades
| Breaks under stress
39
Positives of LDPE
Good electrical insulator
Chemical resistant
Flexible
40
What is the difference between LDPE and HDPE
LDPE is not impact resistant where as HDPE is impact resistant
41
Positives of PVC
```
Good chemical resistance
Weather resistant
Stiff
Tough
Hard
Lightweight
```
42
Negatives of PVC
Brittles over time caused by UV rays from the sun
43
Positives of PP
Light
Hard
Impact resistant
Chemical resistant
44
Uses of PVC
Wiring insulation, pipes, flooring
45
Pp is used for
Syringes and carpets
46
Negatives of PP
UV rays from the sun cause degradation
| Oxidation in manufacture
47
What are the two types of polystyrene
Compressed and expanded
48
Positives of compressed polystyrene
```
Good chemical resistance
Weather resistant
Light
Hard
Stiff
Brittle
Low impact strength
```
49
Uses of compressed PS
Cd cases
Water containers
Fridge linings
50
Positives/negatives of expanded PS
+buoyant lightweight good insulator
-easily ignites
Breaks easily (crumbles)
51
Uses of PS
Packaging
Insulation
Displays
52
ABS +/-
+chemical resistant hard tough
| -degraded by uv light
53
Uses of abs
Mobile phones
| Safety helmets
54
Difference between thermosetting plastics and thermoplastics is
Thermosetting plastics can only be melted and shaped once however thermoplastics can repeatedly be melted down and reshaped/reformed
55
Examples of thermosetting plastics include
Epoxy resins
Polyester resins
Urea formaldehyde
56
Epoxy resins +/-
+Corrosion resistant
Electrical resistant
Good bonding qualities
- can cause allergic reactions
57
Uses of epoxy resins
Adhesives
Paints
Electronics
58
Uses of urea formaldehyde
Electrical fittings
| Domestic appliance components
59
Uses of polyester resins
Glass reinforced boats/cars
| Garden furniture
60
Polyester resins +\-
+good electrical insulator
Heat resistant
-brittle so cracks easily
61
Urea formaldehyde +\-
```
+strong
Hard
Brittle
Heat resistant
-can emit toxic vapours during manufacture
```
62
Types of softwoods include
Pine
63
Pine +\-
+straight/attractive grain
Easily worked
-knots can be seen as unattractive and they're hard to work
64
Uses of pine
Construction
Floorboards
Furniture
65
What defines a softwood
```
Fast growing
Cheap
Easy to walk
Conifer trees
Not necessarily soft
Needles leaves
```
66
Examples of hardwoods
Oak
Mahogany
Beech
67
Features of hardwoods
Broad leaved
Deciduous trees
Slowly grow
More expensive
68
Uses of oak
Construction
Garden furniture
High quality furniture
69
Uses of mahogany
Furniture
Veneers
Floorboards
70
Uses if beech
School desks
| Furniture
71
Examples of man made boards
Mdf
Blackboard
Chipboard
Plywood
72
+\- of oak
```
+strong
Hard
Tough
Aesthetically pleasing
Durable
Works well
- expensive
Heavy
Prone to splitting
Physically hard
```
73
+/- of mahogany
```
+easy to work
Durable
Finishes well
-grain can be variable
Prone to warping
Physical hardness varies
Out of style
```
74
+\- of beech
```
+physically hard
Tough
Polishes well
- prone to warping
Not suitable for outdoor applications
Hard to work
```
75
Mdf is glued ...
Sawdust
76
Chipboard is glued...
Wood chips
77
Blackboard is glued...
Softwood strips
78
Plywood is glued...
Sheets of veneer
79
What are the three types of cams
Eccentric
Pear
Snail
80
What're the three types of follower
Flat
Knife
Roller
81
What is a flat follower like
Most friction
| Cannot follow hollow contours
82
What is a roller follower like
Least friction
Cannot be used to follow hollow contours
Most expensive
83
What is a knife follower like
Most accurate conversion of movement
| Can be used to follow hollow contours
84
Draw all the types of cams
Off centred up and down simple motion for eccentric
Central but dwell period for pear
Used for one direction of motion e.g. Sewing machine for snail
85
Describe a rivet
Permanent joint in metal
86
What do bearings do
Reduce friction and allow shafts to spin more efficiently
87
Define pitch
Distance travelled for one full revolution
88
Name four smart materials
```
Shape memory alloys
Smart paint
Reactive glass
Photochromic paint
Quantum tunnelling composites
```
89
Describe a rack and pinion gear
Changes rotary motion to linear motion
90
Describe a worm and wheel gear
Transmit force and motion through 90degrees
91
Describe a bevel and mitre gear
Can have shafts at 90degrees where different sized gears can change speed
92
Describe a spur gear
Speeds can be increased or decreased as well as the rotation direction being changed
93
What is the key feature of a countersunk screw
It allows a flush finish as it has a flat top
94
What are locked nuts used for
Situations where vibrations are expected
95
How does photochromic paint work
Contains pigments that change colour according to light conditions
96
How do quantum tunnelling composites work
In a relaxed state QTCs are perfect electrical insulators but when stretched/twisted/compressed it becomes an excellent conductor
97
If there is a greater stress on a QTC what is improved
Conductivity
98
Describe and say How does a shape memory alloy work
It is a material that can be deformed by an outside stimulus then, when this stimulus is removed, it'll return to it's original state this stimulus is typically ELECTRICITY
99
What other stimuli apart from electricity can stimulate shape memory alloys
Light
| Pressure
100
Name the 5 modern materials/products
```
Thermo-ceramics
Tinted/photochromic glass
Liquid crystal displays (LCDs)
Solar panels
Electroluminescent lighting
```
101
Describe thermo-ceramics
Advanced ceramic materials that're extremely hard and stable at high temperatures but are brittle and very expensive
102
How are ceramics and metallic powders produced
Sintering
103
What is the sintering process
Powdered metals are heated then placed in a die, subjected to high pressure until the particles bond together
104
What're thermo ceramics used for
Jet engines and turbines
105
What does photochromic glass do and what makes it react as it does?
It darkens when exposed to UV light then turns back to clear glass if reduced or removed
Silver halide particles in the glass are impregnated in the glass
106
What are uses of photochromic glass
Glasses
| Polaroid pictures
107
What is the key downside of photochromic glass
It's irreversible
108
What're LCDs
Organic, carbon based compounds that can exhibit both liquid and solid crystal capabilities
109
What is the key benefit of LCDs
They do not require much energy to power
110
How do solar panels work
They use photovoltaic cells to harness light and convert it to electricity
111
What does the silicon layer in solar panels do to make the light convert to electricity
When sun hits the silicon it becomes electron rich whilst the other side becomes electron deficient causing a voltage to flow which is then harnessed and used as electricity
112
What're are the important benefits and disadvantages to using solar power
Abundantly available and renewable
Expensive to set up
Don't produce much energy
Reliant on the sunlight
113
What does electroluminescent lighting do and how
Converts electrical energy to light by applying a voltage across electrodes
An organic phosphor is between two conductors and they're rapidly charged then emit light
114
What're the +/- of electroluminescent lighting
Extremely low power consumption
The organic phosphor materials used have a limited lifespan
115
What're 4 types of composites
Man made boards
Glass reinforced plastic
Carbon fibre
Laminates
116
How are GRPs made
Thermosetting plastic resin reinforced using very fine glass
117
What does adding glass to resin in a GRP do to it and why should we do this
The glass improves the tensile strength massively of the resin which has an already strong compressive strength but weak tensile without the glass
118
What're the +/- of GRPs
Good strength:weight ratio and very corrosion resistant
Brittle and can shatter easily
When used in boats it can be prone to osmosis
119
What is carbon fibre ideally used for?
High performance structural applications
Sports equipment
Racing cars
120
What is the manufacturing process of carbon fibre/GRPs
1) an expensive, high quality mould is prepared
2) a release agent is sprayed onto the mould otherwise the final product will not be able to be removed from the mould
3) a gel coat is applied to the mould; this is a thin layer of resin that will form the outer skin of the final product
4) layers of resin, catalyst and glass matting are placed into the mould
5) once the layering is complete the work is left to CURE over night then it can be eased out of the mould
121
How are laminates produced
By binding together two or more layers of material
122
What're the key features of laminates
Very stable, don't warp, easy to work, comes in any size, cheap
Worse aesthetics then wood, not good surface finish and thin so can't be jointed like wood (can look cheap)
