1.1 Materials And Their Application

Question 1

Define mechanical property.

Answer 1

How a metal reacts with an external force

Question 2

Define torsional strength

Answer 2

The ability to width stand twisting forces from applied torsion.

Question 3

Define hardness

Answer 3

Ability to resist abrasive wear such as scratching, surface indentation or cutting.

Question 4

Define ductility

Answer 4

Ability to be drawn out under tension, reducing cross section area without cracking

Question 5

Define tensile strength

Answer 5

Ability to resist stretching and pulling forces (tension)

Question 6

Define bending strength

Answer 6

Ability to resist forces that may bend the material

Question 7

Define shear strength

Answer 7

Ability to resist sliding forces on a parallel plane

Question 8

Define plasticity

Answer 8

Ability to permanently deform and retain deformed shape

Question 9

Define malleability

Answer 9

Ability to width stand deformation by compressing without cracking

Question 10

Define compressive strength

Answer 10

Ability to width stand being crushed or shortened by pushing forces

Question 11

Define elasticity

Answer 11

Ability to be deformed and then return to its original shape when the force is removed

Question 12

Define toughness

Answer 12

Ability to absorb impact without fracture

Question 13

What is a physical property

Answer 13

Properties associated with the actual make up or structure of the material

Question 14

What are the two types of electrical properties?

Answer 14

• electrical conductor
• electrical insulator

Question 15

Define electrical conductor
+ example

Answer 15

Allows the flow of electrical current through a material
E.g: silver, aluminium, brass

Question 16

Define electrical insulator
+ example

Answer 16

Does not allow electricity to flow through a material.
E.g: plastic, wood, glass

Question 17

What are the three types of thermal properties?

Answer 17

• thermal conductor
• thermal insulator
• thermal expansion

Question 18

Define thermal conductor
+ example

Answer 18

Allows transfer of heat energy through the material.
E.g: copper, silver, aluminium nitride

Question 19

Define thermal insulator
+ example

Answer 19

Prevents transfer of heat through a material
E.g: fibre glass, polystyrene, mineral wool

Question 20

Define thermal expansion
+ example

Answer 20

Increase in material volume in response to a heat input
E.g: zarconia, alumina

Question 21

What are the three optical properties?

Answer 21

• opaque
• translucent
• transparent

Question 22

Define opaque

Answer 22

Material which prevents light from travelling through

Question 23

Define translucent
+ example

Answer 23

Allows light through but diffuses light so that objects appear blurred.
E.g: frosted glass

Question 24

Define transparent

Answer 24

Allows light to pass through easily, you can see through material easily

Question 25

Define fusibility

Answer 25

Ability of material to be fused or converted from a solid to a liquid usually by heat.

Question 26

Define magnetism

Answer 26

The natural force between objects that causes the material to attract iron or steel.

Question 27

Define corrosion resistance/degradation

Answer 27

Ability of a material to width stand environmental attack and decay

Question 28

Define density

Answer 28

Mass of the material in a standard volume of space

Question 29

What are the three types of metal?

Answer 29

- ferrous - non-ferrous - alloy

Question 30

Define ferrous metal + example

Answer 30

A metal containing mostly iron and carbon, they are magnetic and will rust. E.g: low carbon steel, medium carbon steel, cast iron

Question 31

Define non-ferrous metal + example

Answer 31

A metal that does not contain iron, they are not magnetic and will not rust E.g: aluminium, copper, zinc

Question 32

Define alloy + examples of both ferrous and non ferrous

Answer 32

A metal made of two or more metals or combining two or more elements (one must be metal) E.g: ferrous- stainless steel, die steel Non- ferrous- bronze, brass

Question 33

What are the three types of wood?

Answer 33

- hardwood - softwood - manufactured board

Question 34

Define hardwood + examples

Answer 34

A wood from a deciduous tree, they are slow growing and loose their leaves seasonally E.g: mahogany, oak, teek

Question 35

Define softwood + examples

Answer 35

A wood from a coniferous tree, these are fast growing and are evergreen. E.g: pine, cedar, spruce

Question 36

Define manufactured board + example

Answer 36

A man-made wood-based composite material E.g: plywood, chipboard, MDF

Question 37

What are the three types of polymer?

Answer 37

- thermoforming - thermosetting - elastomer

Question 38

Define thermoplastic polymer + example

Answer 38

A material which can be repeatedly reheated and reshaped, allowing it to be recycled after it’s initial use. E.g: high impact polystyrene, LDPE, HDPE

Question 39

Define thermosetting polymer + example

Answer 39

A material that, when heated, form rigid cross links so they cannot be reformed or reshaped. E.g: polyester resin, epoxy resin, MF

Question 40

Define elastomer + example

Answer 40

A material that can be deformed under pressure in room temperature and upon release of pressure, will return to original shape. E.g: natural rubber, silicone

Question 41

Define smart material + example

Answer 41

A material whose physical properties change in response to an input or change in environment. (Pressure, temp, light) E.g: electroluminescent wire

Question 42

Define modern material + example

Answer 42

A material developed through the invention of new or improved processes. E.g: kevlar, polymorph

Question 43

What are the three common tests for testing hardness? (Industrial test)

Answer 43

- rockwell - brinell - vickers pyramid

Question 44

What is the Rockwell test?

Answer 44

Using a diamond indenter with an added load for a period of time. The smaller the indentation depth the harder the material.

Question 45

What is the Brinell test?

Answer 45

Standard size steel ball is forced into the materials surface using a pre-set load. The smaller the diameter of the indent the harder the material.

Question 46

What is the vickers pyramid test?

Answer 46

Used for very hard materials, using a diamond square based pyramid to ident surface of the material. The smaller the indent the harder the material.

Question 47

What are the four non destructive testing methods?

Answer 47

- ultrasonic - x-ray - electrical conductivity - thermal conductivity