Brief Introduction to How Shape Memory Alloys Work

This website contains information on the mechanism behind the diffusionless phase transformation that occurs in shape memory alloys.  The site is given as:  http://www.doitpoms.ac.uk/tlplib/superelasticity/shape_memory1.php.  Of specific importance to working with shape memory materials are for shape setting you need to anneal the material at 500 deg C, higher than the standard conventional ovens used.  Therefore, to set the temperature a flame or furnace needs to be used.

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Bend Bots

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This picture is of a project called Bend Bots created by Ann Marie Cernoch.   These figures are made using Flexinol wire actuated by an electric current passing through them.  The author notes some important challenges with using the Flexinol wire in regards to attachment of Flexinol to fishing wire.  Flexinol is difficult to solder due to low heat tolerance and the author devises a work around by gluing the Flexinol onto a larger wire and then soldering.  A link describing the Bend Bots is given:  http://www.evl.uic.edu/core.php?mod=4&type=1&indi=385.

 

Shape Memory Alloy Paper Movement

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This picture is an attempt to replicate the folding paper work of Jie Qi at the High-Low Tech Lab at MIT.  Jei Qi’s example of this is called input/output paper with the website:  http://technolojie.com/inputoutput-paper/ and http://fab.cba.mit.edu/classes/MIT/863.10/people/jie.qi/flexinol_intro.html.  For this product, 0.75 mm diameter Nitinol wire was used which is in the Martensitic phase at room temperature and has a Austenite finish temperature around 60 C.  From this initial attempt the main idea learned was the gauge length of the wire is important for paper applications.  Jei Qi uses a material called Flexinol whose diameter is 0.1524 mm, which is significantly lower than the previously used Nitinol.  A video of the paper unfolding can be seen at:  http://youtu.be/Z7m6Y8dL0jo.

Tentacles Shape Memory Alloy Art

This video is of an interactive sculpture of a sea anemone.  The work is made from shape memory alloys and interacts using synchronized light, sound, and motion with the observer.  There 55 silicone tubes with embedded shape memory alloy actuators to create the movement.  The video is from Nakayasu’s Kinetic Art at http://vimeo.com/16378817 and may also be seen at http://goldcrest-alloy.blogspot.com/2011/03/tentacles-akira-nakayasus-kinetic-art.html.