What is Nitinol wire?
Nitinol is an alloy of nickel and titanium that belongs to a class of materials called SHAPE MEMORY ALLOYS (SMA). Nitinol contracts when heated, which is the opposite to standard metals, which expand when heated. Not only does the alloy contract, but also it produces 100 times greater thermal movement (expansion, contraction) than standard metals. Another interesting property of SMA’s is the shaped memory effect (SME). The alloy can be heat-treated to remember a particular shape. Afterwards, if the shape is bent and distorted, the alloy may be heated to regain its original shape.XOT metals manufactures nitinol wire (nickel titanium alloy wire) from various grades of nickel-titanium alloy (Nitinol) commonly used in medical applications as well for other various applications. Medical grade Nitinol material comprises nickel and titanium in nearly equal atomic weight percentages; per ASTM F2063, a nickel content of 54.5-57 wt% is specified for using in surgical implants. Nitinol (nickel titanium alloy) with different compositions and phase transformation temperature can be used for other applications.
Features
- Can remember shapes and return to them even after excessive bending.
- Can be programmed with a new shape at very high temperatures.
- Are superelastic meaning they can undergo exceptional amounts of bending without weakening.
- Is suitable for medical applications
- Exerts force to return to original shape and can even unknot itself while returning to its original shape.
- Can have electric current passed through to induce a shape change.
Durability & Sustainability
Nitinol wire is very durable because of it’s unique internal structure it can undergo repeated bending without becoming work hardened and springs back to form easily. The material will not lose it’s remembered shape over the lifetime of any product it is likely to go into. As for sustainability the material cannot be recycled but can be repurposed easily.
What is the difference between Superelastic and Shape Memory Nitinol?
Superelasticity is a phenomenon when Nitinol gets back to its previous shape and it is very hard to deform. It behaves almost like spring steel. Nitinol is superelastic in two cases:
- if it has temperature slightly over the activation temperature.
- if it is a raw never annealed Nitinol.
Nitinol with shape memory could be easily deformed under the activation temperature. It behaves almost like a tin wire with one difference – it can’t be bend to too acute angles
We suggest you try some and compare it to our regular material to gain a better feel for its characteristics as there may be unexpected pros or cons depending on your application, best identified experimentally.
Contact us so we can help you find the right nitinol wire for your application.