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When the part is heated (usually between 60C and 100C), it returns to its original formed shape, in this case, the helical spring.” However, it is found that alloy of copper-aluminium-nickel, can also have similar properties. It could be created by alloying of zinc, copper, gold and iron which are less expensive compare to Nitinol.
“There are four commonly used types of applications for Nitinol.
- Free Recovery: Nitinol is deformed at a low temperature, and heated to recover its original shape.
- Constrained Recovery: The same, except that recovery is rigidly prevented, and thus a stress is generated.
- Work Production: Here the alloy is allowed to recover, but to do so it must act against a force (thus doing work).
- Superelasticity: As discussed above, here the Nitinol acts as a super spring.”
Therefore, bending paradigm appears to have many innovative applications that designers could create multiple innovations with the help of such metal.
One Way Memory Effect
When a shape memory alloy is in its cold state (below As), the metal can be bent or stretched into a variety of new shapes and will hold that shape until it is heated above the transition temperature. Upon heating, the shape changes back to its original shape, regardless of the shape it was when cold (plate 9). When the metal cools again it will remain in the hot shape, until deformed again. Therefore, the metal remembers its original shape and returns back to it if heated.
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