Materials Flashcards
Oak
Hardwood Properties: hard, tough, durable, high density Uses: furniture, boats, veneers \+ Finishes well - Contains acid which corrodes steel
Mahogany
Hardwood Properties: durable, medium density Uses: indoor furniture + woodwork, window frames, veneers \+ Finishes well \+ Easy to work - Prone to warping
Beech
Hardwood Properties: hard, tough Uses: workshop benches, toys, furniture, kitchen worktops \+ Turns well \+ Finishes well - Prone to warping
Ash
Hardwood Properties: tough, flexible, good elasticity Uses: sports equipment, tool handles \+ Flexible - Can become splintered
Pine
Softwood Properties: lightweight Uses: construction, floorboards, toys, decking \+ Grows fast \+ Nice colour - Prone to warping - Knots can fall out and leave holes
Plywood
Properties: very strong in all directions, resistant to splitting
+ Available in large sheets
+ Doesn’t warp or twist
- Thin sheets are flexible and can warp if unsupported
Chipboard
Structure: waste products bonded using resins. No grain.
Properties: strong in all directions, not very water-resistant
+ Uses waste materials
- Soaks up water
- Edges chip and flake if unprotected
MDF
Properties: very dense, not affected by humidity (stability)
+ Thin sheets can be formed into 2D shapes
- Soaks up water
Hardboard
Properties: side smooth, underside textured
Sructure: fibres soaked in resin and compressed
+ Cheap
- No grain so not very strong
Manufactured boards
+ Dimensional stability
+ Can be painted or have veneers added
+ MDF, chipboard and hardboard can be made from waste
- Sharp tools needed
- Thin sheets bow if unsupported
- Edges must be sealed concealed
- Cutting and sanding creates hazardous particles
Mild steel
Properties: tough, malleable, magnetic \+ Cheap \+ Recyclable \+ Easy to work and join - Will oxidise if unprotected - Can only be case-hardened
Stainless steel
Properties: hard, tough, excellent corrosion resistance \+ Easily cleaned \+ Doesn't need finishing \+ Recyclable \+ High-lustre - Hard to use and join - Specialist welding equipment needed
Carbon steel
Properties: ductile
+ Recyclable
- Will oxidise if unprotected
Aluminium
Properties: lightweight, soft, ductile, malleable, conductive, corrosion resistance \+ Recyclable \+ Easily cast \+ Ductile - Expensive - Specialist welding equipment required
Copper
Properties: malleable, ductile, good conductor, corrosion resistant \+ Ductile \+ Easily soldered \+ Recyclable - Will tarnish - Expensive
Zinc
Properties: excellent corrosion resistance
+ Recyclable
- Brittle
Brass
Properties: corrosion resistant, casts well, good conductor
Composition: 65% copper, 35% zinc
+ Can be polished to a high-lustre finish
+ Tougher than copper
+ Recyclable
+ Easily cast and turned
- Expensive
Acrylic
Thermoplastic Properties: lightweight, good electrical insulator, durable \+ Recyclable \+ Finishes well \+ Available in many colours - Soft, scratches easily - Poor chemical resistance
Polyethene
Thermoplastic Properties: tough, chemically resistant, lightweight, electrical insulator, hard, tough, waterproof, durable \+ Recyclable \+ Cheap - Expensive to recycle - Dangerous fumes released when burnt
High-impact polystyrene
Thermoplastic Properties: tough, high impact strength, electrical insulator \+ Many colours \+ Can be machined and painted \+ Recyclable - Expensive - Will not biodegrade
ABS
Thermoplastic
Properties: tough, high impact strength, lightweight, durable, scratch-resistant, electrical insulator, chemical resistance
+ Many colours
- Expensive
Polyester resin
Thermosetting plastic Properties: electrical insulator, hard, brittle, heat and chemical resistance \+ Many colours \+ Water resistant - Contracts on curing
Urea formaldehyde
Thermosetting plastic Properties: stiff, hard, brittle, high tensile strength \+ Can be coloured \+ Very hard - Toxic fumes given off when curing
Carbon fibre
Properties: lightweight, high tensile strength
Structure: fibres of carbon in a matrix (often epoxy resin)
+ High strength-to-weight ratio
+ High tensile strength
+ Can be woven in pretty patterns
- Very expensive
- Weak in compression and impact
Glass-reinforced plastic
Properties: high tensile and compressive strength, lightweight, durable Structure: glass fibres in a matrix (polyester or epoxy resin) \+ Lightweight \+ Low maintenance \+ Can be formed into any shape \+ Good strength-to-weight ratio \+ Surface textures can be moulded \+ Durable \+ UV and sea salt resistance - Hard to repair - Time-consuming and labour-intensive to make - Needs a mould - Cutting produces harmful dust
Shape memory alloys
Properties: return to original shape when heated
Uses: glasses, braces, anti-scalding valves
+ Good elasticity and tensile strength
+ Lightweight
- Expensive
Photochromic paint
Properties: reversibly changes colour when in UV light
Uses: clothing, vehicles, textiles
- Amount of change depends on level of UV
- Ability decays over time
Reactive glass
Properties: changes colour in UV light or if voltage applied
Uses: transition lenses in glasses, windows
+ Replaces need for separate sunglasses (transition lenses)
- Expensive
- Windows are expensive to install
Carbon nanotubes
Uses: harden paint, strengthen plastics, conductor, medicine \+ Tensile strength \+ Electrical conductor \+ Tough \+ Chemically inert - Expensive - Toxic
