Smart Materials

Question 1

What is a smart material

Answer 1

A material whose physical properties change in response to an input or change in environment, such as electricity, pressure, temperature or light.

Question 2

Shape Memory Alloy

Answer 2

When a metal remembers its shape.
Bent or stretched then when heated return to shape.
Example: Nitinol- most widely used SMA.
Smart wire is the most common form of SMA
Single phase remember one shape or length.

Question 3

Uses of Single Phase Shape memory Alloys

Answer 3

Dental braces, bone plates, screws, locking mechanisms.

Question 4

Uses of dual phase Shape Memory Alloys

Answer 4

Self closing windows, aeroplane wing flaps, bioengineering

Question 5

Thermochromic Pigment

Answer 5

Thermochromic pigment changes colour reversibly when subjected to changes in temperature.
Uses: Thermometers, mugs, kettles, food packaging, baby feeding spoons, battery charge indicator strips.

Question 6

Photochromic Pigment

Answer 6

Photochromic Pigment changes colour reversibly when subjected to changes in light intensity.
Usually, they are colourless in a dark place, and when sunlight or ultraviolet radiation is applied molecular structure of the material changes and it exhibits colour. When the relevant light source is removed the colour disappears.
Changes from one colour to another colour are possible.

Uses: Welding goggles, reactive spectacle lenses, motorbike visors, UV radiation indicators, security markers that show under UV light.

Question 7

Modern Materials: Kevlar.

Properties. Uses.

Answer 7

Aramid fibres with high cut and heat resistance.
Uses:
Body armour, cut proof gloves and clothing, aerospace applications, surfboard components and puncture resistant bicycle tyres.

Question 8

Modern Materials: Precious Metal Clay (PMC)

Answer 8

A clay like material made up of fine metal particles.
It works like ceramic clay, easily mouldable, easy to shape and form.
It sets hard when fired with a kiln or butane torch.
Inexpensive compared to solid metals such as silver

Uses:
Jewellery, decorative items, small sculptures, pendants.

Question 9

Modern Materials: High Density Modelling Foam

Answer 9

Polyurethane closed cell foam blocks or sheets.
Lightweight, easy to cut and shape, sands easily to give a smooth surface.

Uses:
3D CNC routering/milling, modelling, prototypes