Materials

Question 0

Overview of composites:

Answer 0

Natural, fibre, particulate, and dispersion

Question 1

Overview of ceramics:

Answer 1

Electronic materials such as ferries and semiconductors

Constructional ceramics such as porcelain, stoneware, and earthenware

Natural ceramics such as rocks

Glasses such as soda, borosilicate, and pyroceramics

Engineering ceramics such as alumina, carbide, and nitrides

Question 2

Overview of thermoplastic polymers:

Answer 2

Formed by chain-growth polymerisation. Solid at room temperature. Are melted or softened by heating (+/-90 degrees), and can be softened and reformed. They are placed in mould and the. Cooled for desired shape. Can be recycled.

They are used to replace metallic parts as they are lighter. They have high strength and stiffness, and can be reinforced by designing in ribs or strengthening structures. They can hold mechanical properties and dimensional stability up until 80 degrees. They have good impact resistance in relation to their application. Good water and chemical resistance.

Partially crystalline such as polyamide, acetals, and polythene

Amorphous such as pvc, polycarbonates,and polystyrenes

Question 3

Overview of natural polymers:

Answer 3

Cellulose based or protein based

Question 4

Overview of thermoset polymers:

Answer 4

Formed by step-growth polymerisation. Can be liquid or solid at room temperature. They are placed into a moild and then heated to harden (cure) and that is when the chemical reaction occurs. Once formed cannot be reshaped by heating.

Rubbers such as natural, butyl, silicons, nitrile, or styrene

Epoxies such as phenolic (high hardness and stiffness - can replace hard materials such as ivory), aminos (hard and brittle and can be used as adhesives), polyesters, and silicones

Question 5

Overview of ferrous alloy metals:

Answer 5

Plain carbon steel (low/medium/high)

Steels are good for bending and drawing. This is due to the fact that steel has a low carbon content (<0.06% C) and is defect free. It has continuous yielding that allows for good flow if material when forming. It is also a ductile metal.

Alloy steel (low alloy/tool/stainless)

Cast irons (grey, white, malleable, or nodular)

Question 6

Overview of non-ferrous alloy metals:

Answer 6

Light alloys such as zinc, aluminium, magnesium, and titanium

Heavy alloys such as copper, lead, and nickel

Refractory metals such as tungsten, tantalum, and molybdenum

Precious metals such as gold or platinum alloys

Question 7

Give examples of mechanical properties of a material

Answer 7

Strength

Ductility

Fatigue - load goes from compression to tension and cannot take it. A mould has mechanical and thermal fatigue

Hardness

Creep

Strength-to-weight ratio

Stiffness-to-weight ratio

Question 8

Give examples of physical properties of a material

Answer 8

Density

Specific heat

Thermal expansion

Conductivity

Oxidation