Studied by 18 peoplestrength
the ability of a material to withstand a force that is applied to it
tensile strength
the ability to resist a pulling force
compressive strength
the ability to resist a squeezing force eg. ceramics
torsional strength
the ability to resist a twisting force
yield strength
the amount of stress needed to start permanently deforming a material
ultimate tensile strength
the amount of stress at which the material fails
stress =
force/cross-sectional area
ductility
the amount that a material can be deformed eg. nylon
strain =
change in length/original length
malleability
the ability of a material to be deformed without rupturing eg. modelling clay
hardness
the ability of a material to resist wear and abrasion eg. stainless steel
toughness
the ability of a material to withstand an impact without breaking
brittleness
the inability of a material to withstand an impact without breaking
stiffness
the ability of a material to resist bending
the stronger the material and the more it resists deforming, the stiffer it is
young’’s modulus
the ratio of stress to strain of a material, showing how stiff it is
young’s modulus =
stress/strain
ore
rocks or minerals dug from quarries or mines then refined and processed to turn the metal into a usable form
alloy
a mixture of two or more metals
what is the main alloying element of ferrous metals
iron
what type of metal does not contain iron?
non-ferrous
what non-metal makes up a small part of ferrous metals and what is the name of this alloy?
carbon
carbon steel
why isn’t pure iron used in engineering?
it is too soft
increasing the amount of carbon in a ferrous alloy…
increases the hardness and strength of the material
2 pros and 2 cons of cast iron:
pro: good compressive strength, low cost
con: relatively brittle, poor corrosion resistance
2 pros and 2 cons of low- carbon steel:
pro: relatively low cost, tough
con: cannot be hardened, lower strength than other steels
2 pros and 2 cons of high-carbon steel:
pro: strong and hard, can be hardened
con: difficult to form, not as tough as low-carbon steel
2 pros and 2 cons of stainless steel:
pro: good corrosion resistance, strong and hard
con: difficult to machine, relatively expensive
3 examples for non-ferrous alloys:
aluminium, copper, brass
properties of aluminium alloys:
corrosion resistant, lower density, relatively expensive
properties of copper alloys:
good electrical conductor, ductile, good corrosion resistant,
properties of lead alloys:
soft, malleable, ductile, corrosion resistant, high density
properties of zinc alloys:
low melting point
cold working
repeatedly bending or hammering a metal
work hardening
an increase in the strength and hardness of a metal due to cold working
annealing
a heat treatment that makes a metal softer and easier to work
hardening
a heat treatment that increases the hardness and strength of a metal due to a change in the arrangement of the atoms in it
quenching
the rapid cooling of a hot metal by immersing it in a liquid, often oil or brine
tempering
a heat treatment to remove some of the brittleness in a hardened steel, at the cost of some hardness
normalising
a heat treatment that results in metal that is tough with some ductility
corrosion
a reaction between the surface of a material and its environment that consumes some of the material
how would you stop the surface of steel coming into contact with water?
painting, applying a plastic coat, applying a layer of another metal that doesnt react with water, using a sacrificial metal
carburising
the addition of carbon to the surface of a low-carbon steel to improve hardness and strength
polymer
a type of material made from a large number of similar, smaller chemical units that are bonded together
thermoplastic
a type of polymer that can be reshaped when heated
thermosetting polymer
a rype of polymer with cross-links between the polymer chains, cannot be reshaped when heated
what non renewable material are synthetic polymers typically made from?
crude oil
TRUE OR FALSE: Thermoplastics can be recycled
TRUE
which thermoplastic is used to make drink bottles?
polyethylene terephthalate
what thermoplastic is most commonly used to make plumbing pipes?
polyvinyl chloride
what thermoplastic is used to make carrier bags?
low density polythene
what thermoplastic is used to make medical equipment
polypropylene
TRUE OR FALSE: Acrylic is a thermosetting polymer
FALSE
what are some common uses of epoxy?
printed circuit boards, cast electrical insulators
which thermosetting polymer is used to make foam insulation panels and hoses?
polyurethane
what type of polymer are tyres made from
thermosetting vulcanised rubber
composite
a type of material made by combining two or more different types of material, remaining physically distinct
reinforcement
the particles or fibre within a composite matrix that serve to increase its strength
what is the difference between a polymer and a composite?
polymers are chemically bonded whereas composites are simply mixtures
give 2 examples of composite materials
medium density fibreboard (MDF) and plywood
can composites usually be recycled?
no
timber
wood, a type of material obtained from trees
ceramic
a type of material that is typically an oxide, nitride or carbide of a metal
give 2 examples of structural timber
cedar, spruce
what is softwood
wood produced from coniferous trees
what are ceramics used for
building materials such as concrete, lenses, tools for cutting and grinding
can ceramics be recycled?
not usually however glass is an exception
Note
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