unit 5 composite materials Flashcards
mechanical properties
tensile and compressive strength
stiffness and toughness
plasticity and elasticity
ductility and malleability
physical properties
mass,wieght,volume
density and harness
electrical and thermal conductivity
what is tungsten carbide
composite material
made from ceramic and metal
hard, rigid,impact resistant
used in high speed cutting tools
carbon fiber
lightweight, high tensile strength
corrosion/chemical resistant
stable in hot conditions
used in racing cars
glass reinforced platic
strong in tension
little compressive strength
lightweight
uv/corrosion/water resistant
aluminium composite boards
easy to cut
stable, durable,lightweight
range of colours, wont wrap/wrinkle
used in wall panels
fiber cement
was made from cement, asbestos
now made from cellulose and synthetic fibres
lightweight,durable,weather/chemical/rust resistant
used in cladding
concrete
made from air, cement,water,sand,gravel
heavy, high compressive strength,cheap
used in buildings
steel reinforced concrete
used in high rise buildings, bridges and multi story car parks
smart material
one or more properties that is dramatically altered by an external stimulus
shape memory alloys
programmed to remember specific shape at certain temperature
expensive
weather/temp/electrical current stimuli
thermochromic pigment
changes colour/opoacity with change in temp
temp stimuli
phosphorescent pigment
glow in the dark
material absorbs energy from light and emits light in the dark
used in toys paints stickers
light stimuli
photochromic pigment
smart material that changed colour/opacity with uv light in a reversible reaction
used in spectacles, clothing
light stimuli
electroluminescent wire
copper wire coated in phosphor glows when alternative current is applied
flexible, can be used outdoors
used in lighting,bikes,vechicles
electrical current stimuli
piezoelectric materials
convert mechanical energy into electrical
can be stored
used to create spark in lighters
pressure stimuli
What kind of external stimuli might affect a smart material?
Temperature
Moisture
Light Levels
Pressure
what is kevlar
high performance aramid fiber
properties of kevlar
bullet proof, heat and chemical resistant,lightweight,hardwearing,strong,stiff
what is polymorph
thermoplastic which becomes malleable when heated to 62
properties of polymorph
tough durable non toxic biodegradable low melting point
uses of polymorph
enhanced ergonomic designs
moulds and gum shields
what is precious metal clay made of
from precious metal particles held in a water based non toxic binder
properties of pmc
What does PMC stand for?
Precious Metal Clay
What are the uses of PMC?
used to set stones and join PMC parts
What are the properties of HDMF?
lightweight and easy to handle
soft so cuts easy
dented easily
paint and glue will dissolve hdmf
holds good surface detail and fillers
what does HDMF stand for?
High Density Modelling Foam
What is HDMF used for?
makes molds for vacuum forming
What is shape memory alloys used for?
Nitinol
example of thermochromic pigment?
varnishes
kids cup
Phosphorescent examples
fire exit signs
electroluminescent examples
veichles and bikes
piezoelectric examples
crystal
ceramic
bone
What is Tungsten Carbide?
Composite material made from ceramic and metal, known as a cermet.
What are the main properties of Tungsten Carbide?
Extremely hard, rigid, and impact resistant.
How many times harder than steel is Tungsten Carbide?
100 times.
What can scratch Tungsten Carbide?
Only a diamond.
What is a key advantage of Tungsten Carbide at extreme temperatures?
It retains its properties, making it ideal for high-speed cutting tools.
Name two applications of Tungsten Carbide.
Premium kitchen knives, surgical instruments, and jewellery.
What process allows Tungsten Carbide to be formed into complex 3D forms?
Sintering.
Fill in the blank: Tungsten Carbide is known as a _______.
[cermet].
True or False: Tungsten Carbide is less rigid than steel.
False.
What are carbon fibres?
Carbon fibres are several times thinner than a human hair.
What are the properties of carbon fibres?
They are lightweight and have high tensile strength.
How are carbon fibres used?
Fibres are woven into a fabric; the more complex the weave, the more durable the material will be.
What is carbon fibre composite?
Carbon fibre composite is the combination of carbon fibre with a resin, such as vinyl ester or epoxy.
What is Carbon Fibre Reinforced Plastic (CFRP)?
A material used for high tech bike frames, sports equipment, racing cars, crash helmets, and prosthetics.
What are the key properties of CFRP?
Corrosion and chemical resistant, lightweight, stable in hot conditions, tough, hardwearing, and has good tensile strength.
Why is CFRP suitable for wind turbines?
It offers significantly improved stiffness, strength, and fatigue resistance per unit mass compared to fiberglass.
What is GRP commonly known as?
GRP is commonly known as Fibreglass.
What materials are combined to create GRP?
Thermosetting plastics such as polyester or epoxy resin are combined with fibres made of glass.
What are the properties of glass fibres?
Glass fibres are strong in tension with little compressive strength.
What are the properties of resins?
Resins are strong in compression but weak in tension.
What is the result of combining glass fibres and resins?
The combination results in a material that has strengths and weaknesses in tension and compression.
What are the properties of GRP?
Lightweight, high compressive and tensile strength, resistant to UV and corrosion, highly durable and water tight.
What are some applications of GRP?
Used to make complex 3D shapes such as boats, car body panels, and sculptures.
How is GRP formed?
GRP is formed on moulds and layered up in the same way as CFRP - a labour intensive process.
How does the cost of GRP compare to Carbon Fibre?
GRP is far cheaper than Carbon Fibre.
How are the fibres arranged in GRP?
Both arrange the fibres in different directions to achieve rigidity and strength, just like plywood with the grain in each layer running in alternate directions.
What is Aluminium Composite Board?
A composite sheet material combining a polymer core faced with a thin sheet of aluminium.
What are the uses of Aluminium Composite Board?
Used for signage and architectural cladding and wall panels.
What are the properties of Aluminium Composite Board?
Easy to form and cut, stable, durable, lightweight, and resists corrosion.
What finishes are available for Aluminium Composite Board?
Available in a wide range of colours and finishes.
What is the advantage of Aluminium Composite Board for UV printing?
It is the perfect substrate for high quality UV printing.
How does Aluminium Composite Board respond to extreme weather compared to polymers?
It doesn’t expand and contract in extreme weather.
What happens to Aluminium Composite Board over time?
Panels will not warp or wrinkle over time.
What is fibre cement?
A building material used for cladding, roofing, and building facades.
What were the original components of fibre cement?
Originally made from cement and highly toxic asbestos.
What materials are now used in fibre cement?
Cellulose and synthetic fibres are now used instead.
What are the properties of fibre cement?
Durable, lightweight, resistant to rust, weathering, chemicals, and insect attacks.
How does fibre cement affect condensation in buildings?
It’s vapour permeable, reducing any condensation in buildings.
What insulation properties does fibre cement have?
It is a great thermal and noise insulator.
What is a characteristic of fibre cement finish?
It has a smooth finish, creating a sleek, minimalist aesthetic.
How can some fibre cement products be designed?
Some fibre cement products are textured to imitate wood grain for a more traditional aesthetic.
In what forms is fibre cement sold?
Sold in large sheets, slates, or boards.
What is the advantage of using large format sheets of fibre cement?
Large format sheets reduce costs as more surface area can be covered with greater efficiency, saving both time and labour and there’s less waste from offcuts compared to working with traditional cladding.
What is concrete used for?
Concrete is used in buildings, bridges, dams, tunnels, sewage systems, pavements, and roads.
What is concrete made from?
Concrete is a composite made from a mix of several ingredients.
What are the main materials included in concrete?
The main materials included in concrete are air, cement, water, sand, and gravel.
Can the proportions of ingredients in concrete vary?
Yes, the proportions of ingredients can vary depending on the material properties required.
What are the properties of concrete?
Concrete has properties such as being heavy or lightweight, having high or low compressive strength, and being weakened or not weakened by moisture, mould, or pests.
Is concrete a good thermal insulator?
Concrete is considered a bad thermal insulator.
What is the cost of concrete?
Concrete has a low or high cost.
What is the maintenance level of concrete?
Concrete has low or high maintenance.
How much concrete is traded internationally?
Very little or a lot of concrete is traded internationally.
What are the properties of concrete?
Concrete is heavy, has a high compressive strength, is not weakened by moisture, mould or pests, is a good thermal insulator, is low cost, and requires low maintenance.
Is concrete traded internationally?
Very little concrete is traded internationally; it can be locally sourced which reduces CO2.
What is steel reinforced concrete used for?
It is used in high rise buildings, bridges, and multi-storey carparks.
What challenges do high winds and earthquakes pose to concrete?
They put concrete under strain, causing structures to fracture and collapse.
How does steel improve concrete?
Steel improves the strength of concrete under tension and increases its longevity.
Why is it important for steel and concrete to expand and contract at the same rate?
If they do not expand and contract at the same rate, the steel may crack the concrete as temperatures fluctuate.
What is a smart material?
Smart materials have one or more properties that are dramatically altered by an external stimulus.
What properties can be affected by a smart material’s external stimulus?
Properties such as colour, shape, viscosity, volume, and conductivity are affected by a given stimulus.
How do the stimulus and properties of smart materials affect their use?
The stimulus and the properties linked to a smart material affect how and where it is used.
What kinds of external stimuli might affect a smart material?
Various external stimuli can affect smart materials, but specific examples are not provided.
What are smart materials affected by?
Smart materials are affected by external stimuli, which include changes in temperature, levels of light, moisture, and pressure.
How do smart materials respond to environmental changes?
Smart materials show dramatic changes according to subtle environmental differences.
Can you give an example of how traditional materials react to their environment?
Wood swells in moist conditions, and most metals become brittle at extreme temperatures.
What is the process to program a Shape Memory Alloy (SMA)?
An SMA is programmed into a given shape with heat or a high electric current.
How is the desired shape of an SMA maintained during programming?
The SMA is held in the desired shape using a jig, then heated in a furnace, with a flame, or with electric current above the transformation temperature.
What happens to an SMA once it is cooled after programming?
Once cooled, the SMA can be deformed and will return to the shape dictated by the jig when heated.
What determines the activation temperature for reforming an SMA?
The activation temperature needed to stimulate reforming is dictated by subtle changes in the composition of the alloy.
What are some common uses of Shape Memory Alloys (SMAs)?
SMAs are commonly used in glasses frames, orthodontic braces, and heat sensitive valves.
How do SMAs function in orthodontic wire?
Body heat affects the wire, which gently pulls the teeth into position.
Why are SMAs considered expensive?
SMAs are expensive, so they are only commercially viable in high-cost commodities.
How could SMAs be used in a tap?
SMAs could be used in a tap to prevent scalding.
What is thermochromic pigment?
Thermochromic pigment changes colour or opacity with a change in temperature.
Where can thermochromic pigment be mixed?
The pigment can be mixed into materials and finishes such as varnishes, paints, dyes, and polymers.
What transformations can thermochromic pigment undergo?
It may transform from opaque to transparent or change colour.
How can thermochromic pigment be used to improve safety?
Thermochromic pigment can indicate temperature changes, enhancing safety by providing visual cues.
What is thermochromic pigment?
Thermochromic pigment changes colour or opacity with a change in temperature.
Where can thermochromic pigment be mixed?
The pigment can be mixed into materials and finishes such as varnishes, paints, dyes, and polymers.
What transformations can thermochromic pigment undergo?
It may transform from opaque to transparent or change colour.
How can thermochromic pigment be used to improve safety?
Thermochromic pigment can indicate temperature changes, enhancing safety by providing visual cues.
What are phosphorescent materials?
Phosphorescent materials, also known as glow in the dark materials, respond to light.
How do phosphorescent materials work?
They absorb energy from natural or artificial light sources and emit light in the dark.
How long does the glow from phosphorescent materials last?
Typically, the glow will fade within a few hours in a dark environment.
Where are phosphorescent materials commonly used?
They are commonly used in watch faces, toys, stickers, paints, and safety signs, e.g., fire exit signs.
What are phosphorescent materials?
Phosphorescent materials, also known as glow in the dark materials, respond to light.
How do phosphorescent materials work?
They absorb energy from natural or artificial light sources and emit light in the dark.
How long does the glow from phosphorescent materials last?
Typically, the glow will fade within a few hours in a dark environment.
Where are phosphorescent materials commonly used?
They are commonly used in watch faces, toys, stickers, paints, and safety signs, e.g., fire exit signs.
What is a photochromic pigment?
A smart material that changes colour or opacity with the level of ultraviolet light in a reversible reaction.
Where are photochromic pigments commonly used?
In spectacles, clothing, and novelty items.
Can photochromic pigment be used with other materials?
Yes, it can be used as an additive to affect the properties of other materials and finishes.
What is electroluminescent wire made from?
Electroluminescent wire is made from copper wire coated in phosphor.
What happens when an alternating current is applied to electroluminescent wire?
It glows when an alternating current is applied.
What type of coating does electroluminescent wire have?
It has a pliable plastic coating.
Is electroluminescent wire flexible?
Yes, it is flexible and suitable for use outdoors.
How does the light produced by electroluminescent wire compare to LED strip lighting?
Unlike LED strip lighting, EL wire produces a 360° unbroken thread of light.
What are some uses of electroluminescent wire?
It is used in lighting, accessories for bicycles, vehicles, and costumes.
What is electroluminescent wire made from?
Electroluminescent wire is made from copper wire coated in phosphor.
What happens when an alternating current is applied to electroluminescent wire?
It glows when an alternating current is applied.
What type of coating does electroluminescent wire have?
It has a pliable plastic coating.
Is electroluminescent wire flexible?
Yes, it is flexible and suitable for use outdoors.
How does the light produced by electroluminescent wire compare to LED strip lighting?
Unlike LED strip lighting, EL wire produces a 360° unbroken thread of light.
What are some uses of electroluminescent wire?
It is used in lighting, accessories for bicycles, vehicles, and costumes.
