✅3.1 - Types of Materials Flashcards
Types of materials (5)
Plastics / Woods / Metals / Composites / Smart and Modern
Physical properties
An observable/measurable characteristic of material (e.g. strength, density ) which describes how a material behaves under specific conditions
Types of physical properties (8)
Mechanical / Electrical / Chemical / Thermal / Magnetic / Permeability / Aesthetic / Tactile
Mechanical
How a material reacts to physical forces
Example:
How some materials become brittle when repeatedly bent/flexed
Electrical
A material’s conductive properties including insulation and resistance
Example:
How a screwdriver’s polymer handle (insulator) protects the user from electric shocks through the tip (conductor)
Chemical
How a material reacts to other chemicals
Example:
How metals oxidise when exposed (e.g. ferrous metals rusting)
Thermal
How a material responds at different temperatures
Example:
The temperature ranges where thermoforming plastics can be shaped
Magnetic
Most ferrous materials are attracted to magnets or can be magnetised
Example:
The use of magnetic catches for keeping doors closed
Permeability
The degree which liquids or gases can pass through a material
Example:
Woods that have been varnished have low permeability to liquids and water resistance
Aesthetic
The visual sensory properties of the surface/form of a material
Example:
Colour and shine
Tactile
The touch or sensory properties of a material
Example:
Texture
Working properties
The way a material behaves when being worked or shaped of while being used within a product; they determine the tools or processes that will be used when making/manufacturing and how a product will function
Types of working properties (8)
Strength / Hardness / Toughness / Durability / Elasticity / Plasticity / Malleability / Ductility
Strength
The ability to withstand a constant external force without falling
Hardness
The ability to resist wear-and-tear, scratching and dents (usually related to surfaces)
Toughness
The ability to withstand blows or momentary shocks (live forces)
Durability
The ability to resist wear
Example:
Weathering over time
Elasticity
The ability to bend and then return to its original shapes/size
Plasticity
The ability to permanently change shape or form (applies to materials other than polymers)
Malleability
The ability to permanently change shape in all directions while retaining integrity
Ductility
The ability to change shape by stretching along its length without snapping
Why is selecting appropriate materials for a product important?
In order to get the design specification right (identify the requirements of the user, function or conditions that a product will be exposed to)
