NiTi • Nitinol SMA Muscle Wire Shape Memory Alloy
January update: 30C "body heat activated" wire is not available in fine 0.3mm diameter (a little thicker than a hair).
December update: 60C wire is now available in 3 mm thickness. This alloy is uniquely soft at room temperature compared to many other compositions and we urge you to try it if your project requires massive force upon activation at temperatures that are not too hot — almost safe to touch — while still returning to its relaxed martensite form under room temperatures.
Nitinol nickel titanium superalloy heat activated muscle wire 0.5 - 2mm. Transition temps 10 - 80ºC (50 - 180ºF). In stock. Simple ordering. Worldwide shipping.
You can also order a sample pack of each of the available wires here.
The wire has a lustrous titanium color (dark grey) with a bluish oxide tint on its surface. When freshly cut, the inner core is nickel white. Nitinol is very abrasion resistant and has self-healing properties, so the wire is quite hard to cut and kink. It does not require any special handling or protections from oxidation or moisture, and is non-toxic. The best way to damage it is by overheating it, so if you are using electricity instead of hot water to activate it be sure to use a current limiting circuit. Video in slo-mo, ending is at around 16x slow, notice the interesting sound.
Nitinol changes its crystalization pattern at more than 1 temperature point. The stoichiometric ratio of Ni to Ti, impurities, and post-processing determine the mechanical characteristics of your nitinol.
All transition temperatures are specified in Celsius ºC. The temp indicated is an approximation of where the alloy begins to undergo the crystalline transformation. It occurs over a fairly wide temperature range. So, a 40C rated wire will perform faster and stronger at 80C.
At room temperature, an 80C wire will be substantially more malleable and soft to your fingers, the 40C will be more difficult to bend, and the 15C will feel like spring steel. The 15C will react to a heat source up to 80C, while 80C NiTi is more suitable for exposure up to 150C. The 15C will be malleable at and below freezing temperatures.
Return Transition Phase
A common question concerns the ability of the alloy to transition back to its cold shape upon cooling (double dipping). This alloy will exhibit a slight mechanical effect upon cooling, however it does not exhibit nearly the same level of energy as upon heating. The effect is most noticeable in the 15C wire and NiTiCu, however it is mildly present in all of these alloys, and can be emphasized with proper training.
Low Hysteresis variant - NiTi +Cu
An altenate formulation with added copper results in a more pliable nitinol wire referred to as "low hysteresis wire" or NiTiCu. You can select wire with the "Low-H" designation after the transition temperature right on this page.
Low hysteresis wire feels softer. For the same rated temperature, the Low-H wire will be more martensite-dominant than our regular NiTi wire. Low-H wire is also more easily deformed when austenite (hot) and therefore cannot apply the same amount of force as our regular Ni-Ti before reaching plastic deformation.
NiTiCu is more susceptible to "two-way memory". It is easier to train it to change shape upon cooling.
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.
Currently Low-H wire is in stock in 1mm diameter in 30ºC, 40ºC, 60ºC and 80ºC austenite transition temperatures (Af). For a custom spec, please contact us.
- Select your desired unit of measure, and use the quantity selector to choose your ideal length in metric, imperial or by weight.Choose your desired diameter. 0.5mm is 24 gauge, 1mm = 18 gauge, and 2mm = 12 AWG.
- Finally select your transition temperature. Not all sizes are available in all transition temperatures at all times. If checking out is not possible, email us for a custom quote.
- When you order multiple quantities we will cut one long section off of the pictured roll so you can procure uncut sections and cut later as you please.
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