Unit 2-C/D Flashcards
What is an example of a laminated material?
Plywood
How is plywood manufactured?
Veneers layered at 90 degrees and glued together
What are the improved properties of plywood?
The grains go in all directions, so the sheet has strength in all directions
What is an example of reforming a material?
Curved wood parts formed from straight stock material
How are curved wood parts made?
Small scale - using a vacuum bag to curve the material and then glueing it in place
Industrial – steam softening wood and clamping in former (wood can spring back so formers are often exaggerated)
How can rubber be enhanced?
Chemicals can be added to change the properties
What are ceramics?
Made of clay which is a mixture of minerals and natural material
What are the properties of ceramics?
Good strength and durability
Brittle
What are the properties of a thermo-ceramic?
Extremely hard
Very high melting point
Brittle
Expensive
How are thermo-ceramics produced?
Ceramic and metal powders are combined through sintering
What are example uses of thermo-ceramics?
Jet engine turbine blades
Turbos
What are examples of modern materials?
Photovoltaic cells
Thermo-ceramics
Metal foams
Where did solar technology originate?
Space exploration
What is the definition of a smart material?
A material which changes in reaction to changes in its external environment
What are examples of smart materials?
Shape memory alloys
Photochromic glass
Thermochromic paint and materials
Piezoelectric materials
What are the properties and characteristics of shape memory alloys?
Return to original shape if deformed
Expensive
Difficult to machine
Not as strong as traditional metals
What are the properties and characteristics of photochromic glass?
Pigment in glass reacts to light and changes properties causing darkening
What are the properties and characteristics of thermochromic materials and ink?
Ink/material will change colour subject to different temperatures
What are the properties and characteristics of piezoelectric materials?
It will deform when a current is passed through it
It will produce a small voltage when it is deformed
Quartz or ceramic based
What is the most common shape memory alloy?
Nitinol
What are the uses of shape memory alloys?
Braces for teeth
Frames for glasses
Fire alarms
Heating and cooling systems
How does nitinol work?
Programmed to be a certain length or shape at a certain temperature
What are the uses of photochromic glass?
Glass on welding masks
Lenses for sunglasses
What are the uses of thermochromic materials and ink?
Ink on eggs to show if they are boiled
Ink on beer to show if it is cold
Cutlery for children
Bath plug for children
What are the uses of piezoelectric materials?
Contact sensors
Alarms
Microphones
Headphones
