Technical Principles Flashcards
Materials, Manufacture, H&S, Design processes
Classifications of material properties
Mechanical:
compressive strength, tensile strength, hardness, toughness, ductility, malleability
Physical:
electrical properties, thermal properties, aesthetics
Groups of materials
Metals, woods, polymers, papers and boards, smart materials, modern materials
Types of metals
Ferrous, non-ferrous, alloy
Ferrous metals
A metal containing iron and carbon - Mild Steel – Strong, tough, rusts easily, used in car bodies, construction.
Stainless Steel – Corrosion-resistant, tough, used in cutlery & sinks.
Cast Iron – Hard but brittle, used in vices & engine blocks.
Non-ferrous metals
Does not contain iron
Aluminium – Lightweight, corrosion-resistant, used in drink cans, aircraft.
Copper – Conducts electricity & heat, used in wiring & pipes.
Brass (Alloy: Copper + Zinc) – Corrosion-resistant, used in musical instruments.
Alloys
A metal made from 2 or more metals - stainless steel, bronze
Types of woods
Hardwood, softwood, manufactured board
Hardwood
Wood from deciduous trees - lose leaves
Oak – Tough, durable, attractive grain, used in furniture & flooring.
Mahogany – Easy to work, durable, used for high-end furniture.
Beech – Tough, doesn’t splinter, used for toys, tools & furniture.
Ash – Flexible, tough, used in tool handles & sports equipment.
Softwood
Wood from coniferous trees
Pine – Lightweight, easy to work, used for construction & furniture.
Cedar – Resistant to weather & insects, used for outdoor buildings.
Manufactured board
Man-made wood based composite - Plywood – Strong, stable, used in furniture, construction.
MDF (Medium Density Fibreboard) – Smooth, easy to finish, used in furniture.
Chipboard – Cheap, weak unless laminated, used in flat-pack furniture.
Types of polymers
Thermoplastic, thermosetting polymer, elastomer
Thermoplastic
Can be repeatedly heated and reformed and has long linear chain molecules with Van Der Walls forces - Acrylic (PMMA) – Hard, brittle, used in signage & car lights.
Polyethylene (LDPE/HDPE) – Flexible (LDPE) or strong (HDPE), used in bottles & bags.
Polypropylene (PP) – Tough, flexible, used in food containers & chairs.
Polyvinyl Chloride (PVC) – Hard (rigid) or flexible, used in pipes & raincoats.
Thermosetting polymer
When heated, undergoes a chemical change where molecules form rigid cross links
Epoxy Resin – Strong, durable, used in adhesives & electronics.
Melamine Formaldehyde – Heat-resistant, used in kitchen worktops.
Urea Formaldehyde – Hard, electrical insulator, used in plug sockets.
Elastomer
At room temperature can deform and return to its original shape - rubber, silicone
Composites
Material composed of two or more different materials
Carbon Fibre Reinforced Polymer (CFRP) – Lightweight, strong, used in sports equipment & cars.
Glass Fibre Reinforced Polymer (GRP) – Tough, corrosion-resistant, used in boats.
Concrete – Strong in compression, used in buildings.
Smart materials
Physical properties engage in response to and environmental stimuli
Thermochromic Pigments – Change color with heat (used in mugs, forehead thermometers).
Photochromic Pigments – Change color with UV light (used in sunglasses).
Piezoelectric Materials – Generate electricity when deformed (used in sensors).
Modern materials
Material developed through the invention of new or improved processes
Shape Memory Alloy (SMA/Nitinol) – Returns to original shape when heated (used in braces).
