Motion Dynamics

NITINOL COMPONENTS

Nitinol is the common name used for the shape memory alloy Nickel Titanium (NiTi) and is derived from its place of discovery (Nickel Titanium Naval Ordnance Laboratory). It is uniquely different then typical wire alloys used for cold forming or coiling wire components. A reversible, solid phase transformation (known as martensitic transformation) is the force behind shape memory alloys. The material forms a crystal structure, which is capable of undergoing a change from one form of crystal structure to another. Temperature change typically initiates this transformation in the following way:

• Above the transformation temperature – Nitinol is super-elastic, able to withstand deformation when a load is applied and return to its original shape when the load is removed.
• Below the transformation temperature – Nitinol displays the shaped memory effect: when deformed, it will remain in that shape until heated above its transformation temperature, at which time it returns to its original shape.

Nitinol is typically composed of approximately 50 to 55.6% nickel by weight with the balance being titanium. Making small changes in the composition can change the transition temperature of the alloy significantly. These unique properties make Nitinol suitable for many different types of applications, particularly in medical devices.