Shape memory alloy of nickel and titanium displaying superelasticity.
Core Principles & Analysis
Its shape-memory effect was discovered in 1962 by William Buehler and Frederick Wang at the U.S. Naval Ordnance Laboratory, the source of the name NiTiNOL.
It recovers strains of up to about 8% through a reversible martensite-austenite transformation, far beyond the ~0.5% elastic limit of ordinary metals.
Superelastic nitinol forms self-expanding vascular stents and orthodontic archwires that exert a gentle, nearly constant force.