Nitinol Wire，（NITI Wire）Shape Memory Alloy（SMA） WIRE，Shape Memory NiTi Alloy Wire - Superelastic NiTi Alloy Wire

Product Information

Nitinol wire are the fabricating product of nickel-titanium alloy. Nitinol is well known for its thermo-mechanical properties of superelasticity and shape memory effect. Shape memory refers to the ability of Nitinol to undergo deformation at one temperature and then recover its original, under formed shape upon heating above its transformation temperature. Super elasticity occurs at a narrow temperature range just above its transformation temperature; in this case, no heating is necessary to cause the under formed shape to recover, and the material exhibits enormous elasticity, some 10-30 times that of ordinary metal. Nitinol is a nickel-titanium alloy with the typical ratio 40-50% nickel, 50-60% titanium known as a shape memory alloy (SMA), a metal alloy that demonstrates pseudo-elasticity and the shape memory effect. The shape memory effect is when a material returns to its pre-deformed shape by heating. These unusual properties are being applied to a wide assortment of applications in a number of different fields including the medical device and aerospace industries.

Synonyms

Nickel Titanium, shape memory Nitinol, Muscle Wire, Tinel, NiTi, Ni-Ti, nickel-titanium shape-memory alloy (SMA), Alloy N, Alloy M

Nitinol Wire Specification

Dimensions

Size：0.004”-0.2” Diameter, 0.1mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.5mm, customized

Standard：ASTM F2063

AF:-10 ºC(Superelastic)-100 ºC, customized

Surface Finish：Black, Pickled, Polished (Dia.>0.04”)

Forms：Straight wires, Coils, Spools

NiTi

Nitinol nickel titanium superalloy heat activated muscle wire 0.1 - 5mm. Transition temps ranging from -20ºC to 80ºC (-4ºF to 180ºF). customized

Per your request or drawing

We can customized as required

CHOOSING THE RIGHT NITINOL WIRE

Select the wire that is ideal for your temperature. Consider:

·        Activation temperature - the higher temperature that nitinol is subjected to, the faster it will respond. A 40C wire will respond faster to boiling hot water than 80C wire. So for a faster response, use a lower transformation temperature wire.

·        Ambient temperature - higher temperature nitinol wire will return to martensite (soft) faster in warmer environments. A 60C wire will get soft earlier than 40C wire when cooling down in a room that is 30C ambient. In cycle applications, this will allow the cycle to repeat sooner.

·        Diameter - thicker diameter wires exert substantially more force, but take much longer to heat up and cool down, resulting in longer cycle times. Subsequently you may consider using multiple strands of thinner wire.

Nitinol Products

Other: Spherical Nitinol Powder, Nitinol crucibles, Nitinol nuts, Nitinol bolts, Nitinol heating elements, and Nitinol shielding screens.

Properties（Theoretical）

A shape memory alloy undergoes a phase transition changing from one crystal structure to another at a specific temperature, with substantial forces in theprocess. The most common shape memory alloy is Nitinol (Nickel Titanium Naval Ordinance Lab). Variations in the ratio of nickel to titanium and variations in processing create different nitinol characteristics. Nitinol can exhibit a shape memory effect, where it transitions from one crystalline structure to another, and moves with substantial force in the process, upon the application of heat at a temperature specific to the alloy. Super-elastic nitinol, shares the ability of the alloy to stretch up to 30% of its length without permanent deformation, a highly unusual characteristic for a metal. ATT COMPANY both superelastic and shape memory nitinol in wire, sheet, and tube form. For most projects, we recommend wire as it is the least expensive and most versatile form. In comparison, sheet allows you to create 3-dimensional forms that move, and tube allows you to pump heated/cooled fluid directly through the tube for mess-free, highest efficiency activation. Nitinol can be welded in an oxygen-free environment (use shielding gas).

Values listed are for full martensite to      austenite transition.

Similar to 300 series stainless steel or titanium

Highly nonlinear with temperature

Hysteresis can be significantly reduced by      partial transformation or ternary alloys.

CHARACTERISTICS

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.

TRANSITION TEMPERATURES

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.

Applications of Nitinol Wire

Nitinol Wire is used for many different medical and industrial applications. The table below gives some typical engineering applications for each of our standard Nitinol medical grades:

1. Nitinol Wire is used in guidewires, stents,  stylets, forming mandrels, stone retrieval baskets, orthodontic files, etc.

2. Nitinol Wire provides the best cycling performances at body temperature (37°C).

3. A common application for Nitinol alloy is high-temperature actuators.

4. Nitinol Wire/Rod can be used in a very cold temperature environment.

5. Nitinol Wire is often used in applications that require a high loading and unloading plateau stress at room temperature. Chromium-doped for decreased transformation temperature and increased tensile strength.

6. Nitinol Wire is used in applications requiring increased stiffness. Cobalt-doped for decreased transformation temperature and increased tensile strength.

Chemical Identifiers