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nitinol-wireThis week I learned about Nitinol's Fundamentals.

After attending MedTechWorld's MD&M (Medical Device & Manufacturing) Exposition at the Minneapolis Convention Center, I left with a finer comprehension of the manufacturing processes our raw materials undergo after leaving our facility. One of the more interesting metals I had the chance to learn about was Nitinol. This alloy gets its name from being chemically composed of both Nickel and Titanium, and is best known for the ability to retain memory of its previous shape. Nitinol can be heavily deformed but it will revert back to its original shape by simply increasing its temperature.

Like water, Nitinol undergoes phase transformations. Water's phase transformations are water to ice, and water to water vapor. Nitonol has two temperature phases, “martensite” and “austenite.” “Martensite” is a low temperature phase, while “austenite” is a high temperature phase. Going from one phase to the other causes a change in atomic alignment. In order to retain the memory of a given shape, Nitinol is held in the desired shape during the “austenite” phase. Once the shape has formed, the temperature is decreased back to the low temperature, “martensite” phase, while still in the desired shape. This process causes the Nitinol to retain the memory of that shape. Now when Nitinol is deformed and then heated up to revert to its original shape, it is going through the phase change of “martensite” to “austenite.”

Super-elasticity is another special property that Nitinol posses. This allows for you to pull on the material- distorting the shape, but when it is released, it returns back to its original form. This is also possible through phase transformations.

One common use for Nitinol includes eye glasses that use the super-elasticity property so they can bend without breaking. It is also used in several medical devices such as knee replacements and staples.

M. Vincent and Associates distributes Nitinol and would be more then happy to answer any questions you may have. Call today for more information!