Nickel titanium

Nickel titanium, also known as Nitinol (part of shape memory alloy), is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages e.g. Nitinol 55, Nitinol 60. Nickel titanium, also known as Nitinol (part of shape memory alloy), is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages e.g. Nitinol 55, Nitinol 60. Nitinol alloys exhibit two closely related and unique properties: shape memory effect (SME) and superelasticity (SE; also called pseudoelasticity, PE). Shape memory is the ability of nitinol to undergo deformation at one temperature, then recover its original, undeformed shape upon heating above its 'transformation temperature'. Superelasticity occurs at a narrow temperature range just above its transformation temperature; in this case, no heating is necessary to cause the undeformed shape to recover, and the material exhibits enormous elasticity, some 10–30 times that of ordinary metal. The word Nitinol is derived from its composition and its place of discovery: (Nickel Titanium-Naval Ordnance Laboratory). William J. Buehler along with Frederick Wang, discovered its properties during research at the Naval Ordnance Laboratory in 1959. Buehler was attempting to make a better missile nose cone, which could resist fatigue, heat and the force of impact. Having found that a 1:1 alloy of nickel and titanium could do the job, in 1961 he presented a sample at a laboratory management meeting. The sample, folded up like an accordion, was passed around and flexed by the participants. One of them applied heat from his pipe lighter to the sample and, to everyone's surprise, the accordion-shaped strip contracted and took its previous shape.