materiały: Nickel titanium

Evidence: 100 • authority: 72

Nickel titanium, also known as nitinol, is a metal alloy of nickel and titanium, whose two elements are present in roughly equal atomic percentages. Nitinol alloys are named according to the weight percentage of nickel; e.g., nitinol 55 and nitinol 60. Nitinol alloys exhibit two related and unique properties: the shape memory effect and superelasticity (also called pseudoelasticity). Shape memory is the ability of nitinol to undergo deformation at one temperature, stay in its deformed shape when the external force is removed, then recover its original, undeformed shape upon heating above its "transformation temperature". Superelasticity is the ability for the metal to undergo large deformat…

Evidence: 31 • authority: 88

Deformation of Metals by Spherical Indenters ‘Shallowing’ and Elastic ‘Recovery’. Abstract We have already noted that the permanent indentation left in a metal surface deformed by a hard spherical indenter has a larger radius of curvature than that of the indenting sphere. This effect has generally been ascribed to the release of elastic stresses in the specimen. It is at once evident that if this is indeed the case, it should be essentially reversible. That is to say, if the indenter is replaced in the ‘recovered’ indentation and the original load is applied, the surfaces should deform elastically, and on removing the load, the diameter and curvature of the ‘recovered’ indentation should r…