2. Classification of materials Flashcards
What are the classifications of materials?
- metals
- woods
- polymers
- papers and boards
- composites
- smart materials
- modern materials
What is the classification of metals?
- ferrous
- non-ferrous
- alloy
What are ferrous metals?
- a metal containing mostly iron and carbon
- magnetic
- will rust
What are examples of ferrous metals?
- low carbon steel
- medium carbon steel
- cast iron
What are non-ferrous metals?
- a metal that does not contain iron
- not magnetic
- don’t rust
What are examples of non-ferrous metals?
- aluminium
- copper
- zinc
- silver
- gold
- titanium
- tin
What are alloys?
- metal made from two or more metals, or combining two or more elements, one of which must be a metal
- can be sub classified as ferrous alloys and non-ferrous alloys
What are examples of alloys?
- ferrous alloys
- stainless steel
- die steel
- non-ferrous alloys
- bronze
- brass
- duralumin
- pewter
What is the classification of woods?
- hardwood
- softwood
- manufactured board
What are hardwoods?
- wood from broad-leafed trees (deciduous)
- generally slow growing
- lose their leaves in autumn
What are examples of hardwoods?
- oak
- ash
- mahogany
- teak
- birch
- beech
What are softwoods?
- wood from coniferous trees (cone bearing)
- generally fast growing
- tend to be evergreen
What are examples of softwoods?
- pine
- spruce
- Douglas fir
- redwood
- cedar
- larch
What are manufactured boards?
- man-made wood-based composite material
- available in much larger sizes that solid wood
What are examples of manufactured boards?
- plywood
- marine plywood
- aeroply
- flexible plywood
- chipboard
- MDF
What is the classification of polymers?
- thermoplastic
- thermosetting polymer
- elastomer
What are thermoplastics?
- a material which can be repeatedly reheated and reshaped, allowing it to be recycled after initial use
- have long linear chain molecules held by van der Waals forces
What are examples of thermoplastics?
- low density polyethylene (LDPE)
- high density polyethylene (HDPE)
- polypropylene (PP)
- high impact polystyrene (HIPS)
- ABS
- polymethyl methacrylate (PMMA)
- PET
- nylon
- rigid and flexible polyvinyl chloride (PVC)
What are thermosetting polymers?
- a material which when heated undergoes a chemical change whereby the molecules form rigid cross links
- cannot be reheated and reshaped, even at high temperatures
What are examples of thermosetting polymers?
- urea formaldehyde (UF)
- melamine formaldehyde (MF)
- polyester resin
- epoxy resin
What are elastomers?
- materials which at room temperature can be deformed under pressure and then upon release of the pressure, will return to its original shape
- have weak bonds which allow them to stretch easily
- can be stretched repeatedly
What are examples of elastomers?
- natural rubber
- polybutadiene
- neoprene
- silicone
What are papers and boards?
compliant materials (can be scored, cut and folded with basic tooling)
What are examples of papers and boards?
- layout paper
- cartridge paper
- tracing paper
- bleed proof paper
- treated paper
- watercolour paper
- corrugated card
- bleached card
- mount board
- duplex card
- foil backed and laminated card
- metal effect card
- moulded paper pulp
What are composites?
- materials comprised of two or more different materials, resulting in a material with enhanced properties
- can be fibre based (CFRP, GRP fibre concrete)
- can be particle based (tungsten carbide, concrete)
- can be sheet based (aluminium composite board, engineered wood e.g. glulam)
What are examples of composites?
- CFRP
- GRP
- tungsten carbide
- aluminium composite board
- concrete
- fibre cement
- engineered wood e.g. glulam
What are smart materials?
material whose physical properties change in response to an input or change in the environment, such as electricity, pressure, temperature or light
What are examples of smart materials?
- shape memory alloys (SMA)
- thermochromatic pigment
- thermochromatic film
- phosphorescent pigment
- photochromic pigment
- electroluminescent wire
- piezo electric material
What are modern materials?
- material developed through the invention of new or improved processes
- they are not smart materials because they do not react to external change
What are examples of modern materials?
- kevlar
- precious metal clay (PMC)
- high density modelling foam
- polymorph
