Tuesday 6 January 2009

Interesting Memory Metal

Nitinol is a metal alloy that is made from Nickel and Titanium. It is also called 'memory metal' or Shape Memory Alloy (SMA). Shape Memory Alloys have two distinct types of crystal structure, depending on whether they are above or below a certain critical transformation temperature. Below the critical temperature, Nitinol is flexible and can be bent easily into any shape. But once heated to the critical temperature, Nitinol shows its 'heat memory' by springing into its remembered shape.

What are the uses of Nitinol? One use is spectacle frames. Nitinol is soft, so the frames are comfortable to wear. But if they get accidentally bent, you can heat the frames using hot water, and they will spring back to their original shape. Currently Nitinol is quite expensive. But as its cost goes down, there can be many other potential applications. Another possible use is vehicle parts that will repair themselves after an accident.

The 'hot' wire video below demonstrates the properties of Nitinol.

No comments: