Nickel-titanium naval ordnance

As previously mentioned, the nickel—titanium alloys have been the most widely used shape memory alloys. This family of nickel—titanium alloys is known as Nitinol (Nickel Titanium Naval Ordnance Laboratory in honor of the place where this material behavior was first observed). Nitinol have been used for military, medical, safety, and robotics applications. Specific usages include hydraulic lines capable of F-14 fighter planes, medical tweezers, anchors for attaching tendons to bones, eyeglass frames, underwire brassieres, and antiscalding valves used in water faucets and shower heads (38,39). Nitinol can be used in robotics actuators and micromanipulators that simulate human muscle motion. The ability of Nitinol to exert a smooth, controlled force when activated is a mass advantage of this material family (5). 

Another magical titanium material is the alloy nitinol, which can remember a previous shape and return to it. Nitinol consists of 55% nickel and 45% titanium, a combination which corresponds to one atom of nickel for each atom of titanium. This alloy was developed in the US in the 1960s at the Nickel Titanium Naval Ordnance Laboratory which gave rise to the name Ni-Ti-NOL. This alloy is best known as spectacle frames which can be twisted in a way that would be permanently deformed were they to be made of any other metal but, because they are made of nitinol, they will jump back to their original shape when the pressure is removed. 

The most well-known SMA, which exhibits superelasticity above its transformation temperature, is NiTi ( 51% Ni by weight), also known by its trade name, nitinol, for nickel-titanium-naval ordnance laboratory. This alloy was developed in 1959 by William J. Buehler (b. 1923) at the United States Naval Ordnance Laboratory, now the Naval Surface Warfare Center, in White Oak, Maryland. Buehler was looking for a new impact-resistant alloy to serve as the nose cone for a new missile. The alloy s superelastic properties were discovered in 1962 by Frederick E. Wang (b. 1932), whom Buehler hired. The very first observation of superelasticity was by the University of Stockholm chemistry professor Arne Olander, who discovered a rubber-hke effect in an Au-Cd alloy (47.5% Au) in 1932 (Olander, 1932). 

The names Terfenol and Nitinol relate respectively, to Terbium Ferro Naval Ordnance Laboratory and Nickel Titanium Naval Ordnance Laboratory and hence refer to their R D origin. 

The most common SMAs are nickel-titanium alloys and copper alloys of various kinds. Nitinol, a specific alloy of nickel (Ni) and titanium (Ti), is probably the most widely used. (The word nitinol comes from the chemical symbols of its two metal components, along with an abbreviation for the Naval Ordnance Laboratory, where this alloy was discovered and studied in the early 1960s.) Although nickel and titanium alloys tend to be more expensive than copper materi-... 

How can the frames "remember" their original shape when placed in warm water The answer is a nickel-titanium alloy called Nitinol that was developed in the late 1950s and early 1960s at the Naval Ordnance Laboratory in White Oak, Maryland, by William J. Buehler. (The name Nitinol comes from Mckel T/tanium Naval Ordnance Laboratory.) Nitinol has an amazing ability to remember a shape originally impressed in it. 

Shape memory alloys (SMA) undergo solid-to-solid martensitic phase transformations, which allow them to exhibit large, recoverable strains [3]. Nickel-titanium, also known as nitinol (Ni for nickel, Ti for titanium, and nol for Naval Ordnance Lab), are high-performance shape memory alloy actuator materials exhibiting strains of up to 8% by heating the SMA above its phase transformation temperature - a temperature which can be altered by changing the composition of the alloy. 

The titanium-nickel alloys show unusual properties, that is, after it is deformed the material can snap back to its previous shape following heating of the material. This phenomenon is called shape memory effect (SME). The SME of TiNi alloy was first observed by Buehler and Wiley at the U.S. Naval Ordnance Laboratory [Buehler et al, 1963]. The equiatomic TiNi or NiTi alloy (Nitinol) exhibits an exceptional SME near room temperature if it is plasticaUy deformed below the transformation temperature, it reverts back to its original shape as the temperature is raised. The SME can be generally related to a diffusionless martensitic phase transformation which is also thermoelastic in nature, the thermoelasticity being attributed to the ordering in the parent and martensitic phases [Wayman and Shimizu, 1972]. Another unusual... 

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