Shape Memory Alloys (SMA

1
Shape Memory Alloys(SMAs)

• By
• Chris Bomersbach
• MEEN 3344

2
Major Developments

• Buehlers discovery of an NiTi alloy (Nitinol) in
  1962, formed the basis for commercial use. Before
  then shape memory alloys had been observed but
  where not affective enough for practical use.
• SMAs have seen commercial use since the late
  1980s when they where first used for coupling on
  oil pipes.

3
Types

• One way SMAs are the most common type and can be
  deformed when cool, but upon heating, they return
  to their trained shape.
• Two way SMAs can be trained to have a cool shape
  as well as a hot one.
• Different types include
• Ag-Cd 44/49 at. Cd
• Au-Cd 46.5/50 at. Cd
• Cu-Al-Ni 14/14.5 wt. Al and 3/4.5 wt. Ni
• Cu-Sn approx. 15 at. Sn
• Cu-Zn 38.5/41.5 wt. Zn
• Cu-Zn-X (X Si, Al, Sn)
• Fe-Pt approx. 25 at. Pt
• Mn-Cu 5/35 at. Cu
• Fe-Mn-Si
• Pt alloys
• Co-Ni-Al
• Co-Ni-Ga
• Ni-Fe-Ga
• Ti-Pd in various concentrations
• Ni-Ti (55 Ni

http//en.wikipedia.org/wiki/Shape_memory_alloy
4
Ni-Ti

• This video of one way Nitinol can give you an
  idea of just how effective it can be compared to
  conventional metals.
• http//www.youtube.com/watch?vfsBHF_j2FJ4feature
  related
• Nitinol can also be returned to its original
  shape by sending an electric current through it.
  As it resists the electricity, it becomes heated.

5
Pseudo Elasticity

• The most common commercial application involves
  the pseudo-elastic property during its high
  temperature state.
• This includes eye-glasses, cell phone antennas,
  and so on, which are experiencing their high
  temperature state at room temperature.

6
Future Applications

• In the future, if significant steps can taken in
  cost reduction, SMAs will be used for almost
  every metal object. Mail boxes could pop back
  into shape on a sunny day. That slinky you had
  as a child would have lasted longer then thirty
  minutes.
• Imagine getting into a car wreck, then only
  needing to hold a torch to your vehicle to repair
  the damage.
• There are endless new uses for Biomedical
  applications, such as surgical equipment and
  mechanical devices.
• There could also be morphing airplanes and
  submarines that could increase efficiency at
  different speeds.

7
References

• http//www.bio-medicine.org/biology-technology-1/R
  e-Shaping-the-Future-with-Shape-Memory-Alloys---SM
  A-Starter-Kit-10282-1/
• http//www.prudentpressagency.com/modules/news/art
  icle.php?storyid8180
• http//smart.tamu.edu/
• http//www.stanford.edu/richlin1/sma/sma.html