The metal that remembers - Nitinol

Nitinol is a metal that can remember its original shape when heated. This metal has been useful in the medical and space fields.
Interesting Engineering

Imagine a material that self-heals or returns to its original form after being altered. Consider the range of possibilities for applications with such a material. That is Nitinol for you. 

Nitinol was discovered by a young scientist William J Buehler, a metallurgist at the Naval Ordinance Labs, who worked on a team intended to design a nose cone for the Polaris missile project. The material for the same had to withstand the heat generated while the missile re-entered the earth's atmosphere. 

William examined a range of 60 alloys for the project from a book named Constitution of Binary Alloys, with Nitinol being one of the alloys examined. He noticed that the material had a noticeably different double state and named it Nitinol, short for Nickel-Titanium Naval Ordinance Laboratories. 

In 1961, researchers came across the shape-memory aspect of the alloy while experimenting with the fatigue properties of the materials. They noticed that when Nitinol was heated, it rapidly straightened out. 

It was only in 1995 that Nitinol became known to the general public, soon after Nike began using it in its Vision line of eyewear series. A pair of glasses that self-heals if you sit on it or even if it falls from your hand! Nitinol made it possible, as it allowed such glasses to be extremely flexible and return to their original form after being compressed. 

Soon after, Nitinol found its applications in the medical field, where it is being used as a part of vascular stents. The presence of Nitinol meant that the stents could be folded flat to be easily inserted through small holes into the bloodstream, thus minimizing the treatment time. The material can deal with severe deformations and is rated considerably more lasting than stainless steel. 

Nitinol is now widely used for all implants going into the human body, specifically making it an ideal fit for hip replacement material. The metal's super elastic properties enable it to dampen out the vibrations caused when a person moves. 

Nitinol is most widely used in the biomedical field, followed by the eyewear industry. It was also featured on the Nasa Mars mission, with its properties being used 33.6 million miles away. A new wheel with Nitinol as the key component for its tires on Mars rovers allows it to carry more weight, hence letting it hold more instruments for analysis. 

Nitinol holds great promise to be used in a wide range of applications that impact our daily lives.