3.1 Engineering materials

Materials and their properties

Students should have knowledge and understanding of the following groups/classifications of engineering materials. Students should be able to identify these materials based on their physical appearances and the following properties:

toughness/brittleness
ductility
malleability
hardness
strength and stiffness.

Students should also be able to demonstrate knowledge and understanding of the behavioural characteristics of each of these materials during handling/machining.

Metals and alloys

Subject content	Additional information	Mathematical understanding
Ferrous metals and alloys: cast iron low and high carbon steels steel alloys (stainless steel). Non-ferrous metals and alloys: aluminium copper lead zinc alloys (brass and bronze).	Students will not be expected to have practical experience of working with all of these metals/alloys but exam questions could refer to any of the properties listed. Students should also be able to demonstrate knowledge and understanding of how the mechanical properties of these metals can change through: the addition of materials to form alloys methods which affect the grain size (heating) cold working hardening and quenching corrosion addition/subtraction of carbon in steels.

Subject content

Additional information

Mathematical understanding

Ferrous metals and alloys:

cast iron
low and high carbon steels
steel alloys (stainless steel).

Non-ferrous metals and alloys:

aluminium
copper
lead
zinc
alloys (brass and bronze).

Students will not be expected to have practical experience of working with all of these metals/alloys but exam questions could refer to any of the properties listed.

Students should also be able to demonstrate knowledge and understanding of how the mechanical properties of these metals can change through:

the addition of materials to form alloys
methods which affect the grain size (heating)
cold working
hardening and quenching
corrosion
addition/subtraction of carbon in steels.

Polymers

Subject content	Additional information	Mathematical understanding
Thermoplastics: ABS acrylic nylon polycarbonate polystyrene. Thermosetting polymers: epoxy polyester and melamine resins polyurethanes vulcanised rubber.	Students will not be expected to have practical experience of working with all of these polymers but exam questions could refer to any of the properties listed. The effects of heat on thermosets and thermoplastics.

Subject content

Additional information

Mathematical understanding

Thermoplastics:

ABS
acrylic
nylon
polycarbonate
polystyrene.

Thermosetting polymers:

epoxy
polyester and melamine resins
polyurethanes
vulcanised rubber.

Students will not be expected to have practical experience of working with all of these polymers but exam questions could refer to any of the properties listed.

The effects of heat on thermosets and thermoplastics.

Composites

Subject content	Additional information	Mathematical understanding
Fibre reinforced polymers (FRP): carbon-fibre reinforced polymer glass reinforced plastic (GRP). Plywood. Medium Density Fibre board (MDF). Oriented Strand Board (OSB). Structural concrete.	Students will not be expected to have practical experience of working with all of these composites but exam questions could refer to any of the properties listed. Students should also be able to demonstrate knowledge and understanding of how the mechanical properties of these materials can change through the: direction/alignment of reinforcement matrix in which the reinforcement is placed amount of reinforcement used size and shape of reinforcement.

Subject content

Additional information

Mathematical understanding

Fibre reinforced polymers (FRP):
- carbon-fibre reinforced polymer
- glass reinforced plastic (GRP).
Plywood.
Medium Density Fibre board (MDF).
Oriented Strand Board (OSB).
Structural concrete.

Students will not be expected to have practical experience of working with all of these composites but exam questions could refer to any of the properties listed.

Students should also be able to demonstrate knowledge and understanding of how the mechanical properties of these materials can change through the:

direction/alignment of reinforcement
matrix in which the reinforcement is placed
amount of reinforcement used
size and shape of reinforcement.

Other materials

Subject content	Additional information	Mathematical understanding
Timbers (structural grades). Ceramics.	Students will not be expected to have practical experience of working with all of these materials but exam questions could refer to any of the properties listed.

Material costs and supply

Students should have knowledge and understanding of the cost, availability, form and supply of the engineering materials listed in Materials and their properties.

Subject content	Additional information	Mathematical understanding
Cost, availability, form and supply of the metals, alloys, polymers, composites and other materials listed.	Students will be expected to know the comparative costs of different materials within and across these groups eg copper vs gold for use as electrical components or timber vs steel for structural components. Students will not be asked questions about specific aspects of individual materials in the exam, but they will be expected to demonstrate their understanding of the benefits to designers and manufacturers of having a choice of materials to work with. They will also be expected to provide and discuss at least three examples.
Calculation of costs to manufacture/produce items to inform the development of an engineered solution in industry.	Students will be expected to understand the following: available stock sizes and supply using economies of scale to reduce costs (price breaks based on quantity) waste produced.	E1, E2, E3, E4, E5 M1.1, M1.2
The ability of engineering materials to be: machined treated shaped recycled.	Students will be expected to be familiar with these concepts in relation to the materials listed.

Subject content

Additional information

Mathematical understanding

Cost, availability, form and supply of the metals, alloys, polymers, composites and other materials listed.

Students will be expected to know the comparative costs of different materials within and across these groups eg copper vs gold for use as electrical components or timber vs steel for structural components.

Students will not be asked questions about specific aspects of individual materials in the exam, but they will be expected to demonstrate their understanding of the benefits to designers and manufacturers of having a choice of materials to work with.

They will also be expected to provide and discuss at least three examples.

Calculation of costs to manufacture/produce items to inform the development of an engineered solution in industry.

Students will be expected to understand the following:

available stock sizes and supply
using economies of scale to reduce costs (price breaks based on quantity)
waste produced.

E1, E2, E3, E4, E5

M1.1, M1.2

The ability of engineering materials to be:

machined
treated
shaped
recycled.

Students will be expected to be familiar with these concepts in relation to the materials listed.

Factors influencing design of solutions

Subject content	Additional information	Mathematical understanding
Energy production methods: wind solar tidal nuclear fossil fuels biomass.	Students will need to understand the benefits and drawbacks of each of the energy production methods listed including any possible environmental impact.
Engineered lifespans.	Planned obsolescence. Sealed parts. Maintenance requirements.
The need for and methods of maintenance of engineered products.	Students will be expected to understand the need for maintenance of engineered products to: ensure safety in operation enable efficiency of operation. They will also need to understand the reasons for the following types of maintenance work: lubrication avoiding corrosion compensating for wear End of Life (EOL), disposal and recovery of materials.	Measurement and tolerances M1.1, M1.2, M1.3
	Understand that statistics can be used to predict service intervals and expected lifetime of components.	M2.2, M2.4
Engineered solutions can be inhibited by the availability and forms of materials.	Cost is affected by the availability of materials, and using non-standard forms will increase cost.	M1.4
How user requirements affect material choice and manufacturing process.	Users requiring solutions that are higher strength or lower weight means choosing materials such as titanium or carbon fibre composites, and may require more specialist manufacturing processes.	M1.4

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3.2 Engineering manufacturing processes