8.2 - Material Classification

Question 1

Types of Engineering materials?

Answer 1

Metals (1-3 valance electrons)

Non-metals (4-8)

Question 2

Types of metals?

Answer 2

Ferrous (contain iron)

Non-ferrous metals

Question 3

Types of Ferrous metals?

Answer 3

Wrought Iron (<0.008% carbon)
Steels (alloy of iron, carbon, and possibly more)
Cast Irons (>2% carbon)

Question 4

Types of Steels?

Answer 4

Alloy Steels (iron, carbon, and more)
Plain carbon steels (iron and carbon)

Question 5

Types of Non-metals?

Answer 5

Synthetic materials / Plastics (man-made, consist of wide range of carbon based compounds with molecules of high molecular mass)
Natural materials (from plants, animals, ground)

Question 6

Examples of Natural materials?

Answer 6

Rubber
Glass
Wood
Ceramics
Diamond
Oil

Question 7

Types of Synthetic materials?

Answer 7

Thermoplastics (heated, do not undergo chemical change, can be moulded)
Thermosetting plastics (heated, melt and take shape only once, irreversible chemical reaction)

Question 8

Classes of materials?

Answer 8

Metals
Polymers
Ceramics
Composites

Question 9

Metal qualities?

Answer 9

Hard
Opaque
Good heat / electrical conductors
Shiny
Malleable (can be pressed perm. without braking)
Ductile (drawn into thin wire)

Question 10

Metal examples?

Answer 10

Steel
Copper
Aluminium

Question 11

What’s an alloy?

Answer 11

Mixture of a metal and other elements, made for unique qualities

Question 12

What is heat treatment?

Answer 12

A metal, like hard steel, is heated and rapidly cooled in oil or water (quenching) to strengthen it

Question 13

Polymer qualities?

Answer 13

Consist of large molecules, composed of many repeating sub-units (joined by polymerisation)
Malleable (can be moulded)

Question 14

Polymer examples?

Answer 14

PVC (polyvinyl chloride)

PTFE (polytetrafluoroethylene), eg. Teflon

Question 15

What’s an elastomer?

Answer 15

Rubbers that can be stretched, have large elastic strains, eg. car tyres and elastic bands

Question 16

Ceramic qualities?

Answer 16

Hard
Brittle (tension and compression)
Good insulators
Good chemical resistance
High melting temps (formed whilst in powder form, with water and heat)

Question 17

Ceramic composition?

Answer 17

Chemical compound formed of oxides such as silica (sand), sodium and calcium, as well as silicates (eg. clay)

Question 18

Ceramic examples?

Answer 18

Glass (contains silica)
Brick / clay
Kaonlinite (traditional raw ceramic)
Alumina / ali oxide (new raw)

Question 19

Composite composition?

Answer 19

Made from two or more constituent materials with significantly different physical / chemical properties, the individual components remain separate and distinct in the finished structure

Question 20

Alloy examples?

Answer 20

Brass - copper and zinc

Stainless steel - iron, carbon, nickel and chromium

Question 21

Composite examples?

Answer 21

Reinforced concrete is made from steel and concrete (steel good for tension, concrete good for compressive loads)
Fibre reinforcement of a resin matrix (light, stiff, strong and tough)
Bones