Nickel Titanium (also known as Nitinol or NiTi) is in the unique class of shape memory alloys. A thermoelastic martensitic phase transformation in the material is responsible for its extraordinary properties. Nitinol alloys are typically made of 55%-56% Nickel and 44%-45% Titanium.
Small changes in composition can significantly impact the properties of the material. There are two primary categories of Nitinol. The first, known as "Super-elastic", is characterized by extraordinary recoverable strains and kink resistance. The second category, "Shape Memory" alloys, is valued for the Nitinol's capacity to recover a pre-set shape when heated above its transformation temperature.