topic 2- performance characteristics of materials Flashcards
what is an electrical conductor
allows flow of electric current through
what is an electrical insulator
does not allow flow of electric current
what is a thermal conductor
allows transfer of heat energy through
what is a thermal insulator
prevents the transfer of heat through a material
what is strength and example of strong material
The ability of a material to stand up to forces being applied without it bending, breaking, shattering or deforming in any way.
carbon fibre
what are the different types of strength
bending - resist forces that bend
compressive- withstand being crushed
tensile strength - resist stretching
shear strength - resist sliding forces
torsional strength - withstand twisting
what is elasticity
The ability of a material to absorb force and flex / be deformed in different directions, returning to its original position.
eg. plywood skateboard
what is plasticity
ability to be permanently deformed and retain deformed shape
what is malleability
The ability of a material to be reshaped in all directions without cracking. incr with rising temps
what is ductility
The ability of a material to change shape (deform) usually by stretching along its length.
eg PVC hose
what is hardness
ability to resist abrasive wear eg scratching and indentation
what is toughness
A characteristic of a material that does not break or shatter when receiving a blow or under a sudden shock.
eg aluminium nails
what is durability
ability to withstand general wear over time
what is biodegradability
ability to naturally decompose by actions of bacteria or organisms
how are they made and what are the perform characteristics of wood
- can change by expanding or shrinking with changes in humidity
- sawn into suitable pieces and then excess moisture is removed
- helps prevent twisting and cracks
- strong in the direction of grain
- natural material and will biodegrade
how are they made and what are the perform characteristics of metals
- naturally occurring material and mined from ground from ore
- 25% of earths crust made of metal ores
- raw metal is extracted using crushing, smelting or heating
- can easily be recycled
how are they made and what are the perform characteristics of polymers
- most made via fractional distillation of crude oil
( non renewable) - take hundreds of years to degrade
- self finishing as can be pigmented in process so do not need added coat
how are they made and what are the perform characteristics of smart and modern materials
- materials who’s physical properties change in response to an input or change in environment eg temp electricity or light
- developed through invention of new or improved processes
- will continue to be made due to tech advances
- eg thermochromic material
how are they made and what are the perform characteristics of papers and boards
- can be scored folded and cut with basic tooling
- made with wood pulp
- bleaches often added to make paper whiter
- come from natural source and will naturally biodegrade
how are they made and what are the perform characteristics of textiles
- natural fibres from plants or animals
- naturally reoccurring and can be recucled
- good breathability
- manmade fibres do not occur naturally and are synthetic
- mainmast do not absorb liquid
- can be treated to become flame and stain resistant
