Nitinol(also known as Nickel-Titanium or NiTi) is a metal alloy, sometimes also called Shape Memory Alloy (SMA). Nitinol alloys exhibit two closely related and unique properties: one of which is superelasticity occurs in a narrow temperature range just above the transformation temperature. An elastic (reversible) responses to an applied temperature, caused by a phase transformation between the austenitic and martensitic phases of a crystal.

Superelastic nitinol is characterized by extraordinary recoverable strains.

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