Shape memory alloy is applied to that group demonstrate the ability to return in some previously defined shape Properties: Some materials undergo change in shape upon recooling. This rearrangement occurs because temperature change is of only $100^oC$

There are two phases which occurs in shape memory alloy

1. Martensite –low symmetry at low temperature
2. Austenite – High symmetry at high temperature (highly systematic and crystalline structure)

Phase change occur due to rearrangement and some alloys changes shape with small difference in temperature.

Applications of shape memory alloy: Shape memory effect is currently implemented in

• Coffeepot
• The space shuttle
• Thermostat
• Vascular stent
• Dental braces that exerts constant pressure on teeth

Example:

1. TiNi alloy
2. CuAlNi alloy
3. CuAlZnNi alloy